diff --git a/src/js/Aladin.js b/src/js/Aladin.js
index de78bf5b..e33cfbdf 100644
--- a/src/js/Aladin.js
+++ b/src/js/Aladin.js
@@ -568,7 +568,8 @@ export let Aladin = (function () {
     Aladin.prototype.setProjection = function (projectionName) {
         console.log('setProj', projectionName);
         this.webglAPI.setProjection(projectionName);
-
+        this.view.fov_limit = this.webglAPI.getMaxFieldOfView() * 180 / Math.PI;
+        console.log("FOV LIMITE", this.view.fov_limit);
         /*
         if (!projectionName) {
             return;
@@ -1096,7 +1097,7 @@ export let Aladin = (function () {
 
         layerBox.append('<div class="aladin-box-separator"></div>' +
             '<div class="aladin-label">Projection</div>' +
-            '<select id="projectionChoice"><option value="orthographic">SINUS</option><option value="aitoff">AITOFF</option><option value="mercator">MERCATOR</option><option value="arc">ARC</option></select><br/>');
+            '<select id="projectionChoice"><option value="orthographic">SINUS</option><option value="aitoff">AITOFF</option><option value="mollweide">MOLLWEIDE</option><option value="mercator">MERCATOR</option><option value="arc">ARC</option><option value="gnomonic">TAN</option></select><br/>');
 
         $('#projectionChoice').change(function () {
             aladin.setProjection($(this).val());
diff --git a/src/js/View.js b/src/js/View.js
index a2aa321c..398bcbb2 100644
--- a/src/js/View.js
+++ b/src/js/View.js
@@ -115,6 +115,7 @@ export let View = (function() {
             this.mode = View.PAN;
             
             this.minFOV = this.maxFOV = null; // by default, no restriction
+            this.fov_limit = 180.0;
             
             this.healpixGrid = new HealpixGrid(this.imageCanvas);
             if (cooFrame) {
@@ -402,7 +403,8 @@ export let View = (function() {
         // if zoom factor < 1, we view 180°
         var fov;
         if (view.zoomFactor<1) {
-            fov = 180;
+            console.log(view.fov_limit)
+            fov = view.fov_limit;
             //fov = 360;
         }
         else {
@@ -418,7 +420,7 @@ export let View = (function() {
             fov = new Coo(lonlat1.ra, lonlat1.dec).distance(new Coo(lonlat2.ra, lonlat2.dec));
         }
 
-        fov = Math.min(360, fov);
+        fov = Math.min(view.fov_limit, fov);
         
         return fov;
     }
@@ -730,6 +732,9 @@ export let View = (function() {
                 //pos2 = view.projection.unproject(xy2.x, xy2.y);
                 pos1 = webglAPI.screenToWorld(view.dragx, view.dragy);
                 pos2 = webglAPI.screenToWorld(e.originalEvent.targetTouches[0].clientX, e.originalEvent.targetTouches[0].clientY);
+                if (pos2 == undefined)  {
+                    return;
+                }
             }
             else {
                 /*
@@ -746,6 +751,10 @@ export let View = (function() {
 
                 pos1 = webglAPI.screenToWorld(view.dragx, view.dragy);
                 pos2 = webglAPI.screenToWorld(xymouse.x, xymouse.y);
+
+                if (pos2 == undefined)  {
+                    return;
+                }
             }
             
             // TODO : faut il faire ce test ??
@@ -1556,18 +1565,26 @@ export let View = (function() {
     
     View.prototype.computeZoomFactor = function(level) {
         if (level>0) {
-            return AladinUtils.getZoomFactorForAngle(180/Math.pow(1.15, level), this.projectionMethod);
+            return AladinUtils.getZoomFactorForAngle(this.fov_limit/Math.pow(1.15, level), this.projectionMethod);
         }
         else {
             return 1 + 0.1*level;
         }
     };
+    /*View.prototype.computeZoomLevelFromFOV = function() {
+        if (level>0) {
+            return AladinUtils.getZoomFactorForAngle(180/Math.pow(1.15, level), this.projectionMethod);
+        }
+        else {
+            return 1 + 0.1*level;
+        }
+    };*/
     
     View.prototype.setZoom = function(fovDegrees) {
-        if (fovDegrees<0 || (fovDegrees>180 && ! this.aladin.options.allowFullZoomout)) {
+        if (fovDegrees<0 || (fovDegrees>this.fov_limit && ! this.aladin.options.allowFullZoomout)) {
             return;
         }
-        var zoomLevel = Math.log(180/fovDegrees)/Math.log(1.15);
+        var zoomLevel = Math.log(this.fov_limit/fovDegrees)/Math.log(1.15);
         this.setZoomLevel(zoomLevel);
     };
     
@@ -1587,29 +1604,30 @@ export let View = (function() {
             zoom["action"] = "zoom";
         }*/
 
-        if (this.minFOV || this.maxFOV) {
+        /*if (this.minFOV || this.maxFOV) {
             var newFov = doComputeFov(this, this.computeZoomFactor(Math.max(-2, level)));
             if (this.maxFOV && newFov>this.maxFOV  ||  this.minFOV && newFov<this.minFOV)  {
                 return;
             }
-        }
+        }*/
 
-        if (this.projectionMethod==ProjectionEnum.SIN) {
+        /*if (this.projectionMethod==ProjectionEnum.SIN) {
             //this.zoomLevel = Math.max(-2, level); // TODO : canvas freezes in firefox when max level is small
             this.zoomLevel = Math.max(-7, level); // TODO : canvas freezes in firefox when max level is small
         } else {
             this.zoomLevel = Math.max(-7, level); // TODO : canvas freezes in firefox when max level is small
-        }
-        
+        }*/
+        this.zoomLevel = Math.max(-7, level);
         
         this.zoomFactor = this.computeZoomFactor(this.zoomLevel);
         
         var oldFov = this.fov;
         this.fov = computeFov(this);
+        console.log(this.zoomLevel, this.fov);
+
         if (this.zoomFactor >= 1.0) {
             this.aladin.webglAPI.setFieldOfView(this.fov);
         } else {
-
             console.log("FOV, ", this.fov / this.zoomFactor);
 
             // zoom factor
diff --git a/src/render/src/buffer/hips_config.rs b/src/render/src/buffer/hips_config.rs
index 00b552b5..9af14712 100644
--- a/src/render/src/buffer/hips_config.rs
+++ b/src/render/src/buffer/hips_config.rs
@@ -153,14 +153,18 @@ impl HiPSConfig {
                         tex_storing_integers = 1;
                         Ok(FormatImageType::FITS(FITS::new(WebGl2RenderingContext::R16I as i32)))
                     },
-                    /*32 => {
+                    32 => {
                         tex_storing_integers = 1;
                         Ok(FormatImageType::FITS(FITS::new(WebGl2RenderingContext::R32I as i32)))
-                    },*/
+                    },
                     -32 => {
                         tex_storing_integers = 0;
                         Ok(FormatImageType::FITS(FITS::new(WebGl2RenderingContext::R32F as i32)))
                     },
+                    -64 => {
+                        tex_storing_integers = 0;
+                        Ok(FormatImageType::FITS(FITS::new(WebGl2RenderingContext::R32F as i32)))
+                    },
                     _ => {
                         Err(format!("Fits tiles exists but the BITPIX is not correct in the property file").into())
                     }
diff --git a/src/render/src/buffer/image.rs b/src/render/src/buffer/image.rs
index f8c9c04d..7410899e 100644
--- a/src/render/src/buffer/image.rs
+++ b/src/render/src/buffer/image.rs
@@ -643,7 +643,6 @@ impl ImageRequest for FITSImageRequest {
         //crate::log(&format!("bytes {:?}", bytes));
         if let Ok(Fits { data, header }) = Fits::from_bytes_slice(bytes) {
             let num_channels = format.get_num_channels() as i32;
-            //crate::log(&format!("data {:?}", data));
 
             let image = match data {
                 DataType::U8(data) => {
@@ -659,7 +658,8 @@ impl ImageRequest for FITSImageRequest {
                     TileArrayBufferImage::F32(TileArrayBuffer::<ArrayF32>::new(&data.0, tile_width, num_channels))
                 },
                 DataType::F64(data) => {
-                    TileArrayBufferImage::F64(TileArrayBuffer::<ArrayF64>::new(&data.0, tile_width, num_channels))
+                    let data = data.0.into_iter().map(|v| v as f32).collect::<Vec<_>>();
+                    TileArrayBufferImage::F32(TileArrayBuffer::<ArrayF32>::new(&data, tile_width, num_channels))
                 },
                 _ => unimplemented!()
             };
diff --git a/src/render/src/buffer/image_survey_buffer_textures.rs b/src/render/src/buffer/image_survey_buffer_textures.rs
index 61289785..e8cdc827 100644
--- a/src/render/src/buffer/image_survey_buffer_textures.rs
+++ b/src/render/src/buffer/image_survey_buffer_textures.rs
@@ -218,7 +218,7 @@ impl ImageSurveyTextures {
 
     // This method pushes a new downloaded tile into the buffer
     // It must be ensured that the tile is not already contained into the buffer
-    pub fn push<I: Image + 'static>(&mut self, tile: Tile, image: I, time_request: Time) {
+    pub fn push<I: Image + 'static>(&mut self, tile: Tile, image: I, time_request: Time, missing: bool) {
         let tile_cell = tile.cell;
         // Assert here to prevent pushing doublons
         if self.contains_tile(&tile_cell) {
@@ -283,7 +283,8 @@ impl ImageSurveyTextures {
         if let Some(texture) = self.textures.get_mut(&texture_cell) {
             texture.append(
                 &tile_cell, // The tile cell
-                &self.config
+                &self.config,
+                missing
             );
             // Compute the cutoff of the received tile
             //let cutoff = image.get_cutoff_values();
diff --git a/src/render/src/buffer/texture.rs b/src/render/src/buffer/texture.rs
index 815ac538..bcc7cbbe 100644
--- a/src/render/src/buffer/texture.rs
+++ b/src/render/src/buffer/texture.rs
@@ -34,6 +34,7 @@ pub struct Texture {
     // Flag telling whether the texture is available
     // for drawing
     is_available: bool,
+    missing: bool,
 }
 
 use crate::buffer::HiPSConfig;
@@ -48,6 +49,7 @@ impl Texture {
         let texture_cell = *texture_cell;
         let uniq = texture_cell.uniq();
         let is_available = false;
+        let missing = true;
         let num_tiles_written = 0;
         Texture {
             texture_cell,
@@ -59,6 +61,7 @@ impl Texture {
             full,
             is_available,
             num_tiles_written,
+            missing
         }
     }
 
@@ -67,12 +70,15 @@ impl Texture {
     // Return true if the tile is newly added
     pub fn append(&mut self,
         cell: &HEALPixCell,
-        config: &HiPSConfig
+        config: &HiPSConfig,
+        missing: bool
     ) {
         let texture_cell = cell.get_texture_cell(config);
         assert!(texture_cell == self.texture_cell);
         assert!(!self.full);
 
+        self.missing &= missing;
+
         // cell has the good ancestor for this texture
         let new_tile = self.tiles.insert(*cell);
         // Ensures the tile was not already present in the buffer
@@ -163,6 +169,7 @@ impl Texture {
         self.time_request = time_request;
         self.tiles.clear();
         self.is_available = false;
+        self.missing = true;
         self.num_tiles_written = 0;
     }
 
@@ -214,6 +221,7 @@ impl<'a> SendUniforms for TextureUniforms<'a> {
     fn attach_uniforms<'b>(&self, shader: &'b ShaderBound<'b>) -> &'b ShaderBound<'b> {
         shader.attach_uniform(&format!("{}{}", self.name, "uniq"), &self.texture.uniq)
             .attach_uniform(&format!("{}{}", self.name, "texture_idx"), &self.texture.idx)
+            .attach_uniform(&format!("{}{}", self.name, "empty"), &(self.texture.missing as i32))
             .attach_uniform(&format!("{}{}", self.name, "start_time"), &self.texture.start_time());
 
         shader
diff --git a/src/render/src/lib.rs b/src/render/src/lib.rs
index 28b1a386..995df62b 100644
--- a/src/render/src/lib.rs
+++ b/src/render/src/lib.rs
@@ -552,7 +552,9 @@ impl App {
         self.look_for_new_tiles();
         self.request_redraw = true;
     }
-
+    fn get_max_fov<P: Projection>(&self) -> f32 {
+        P::aperture_start().0
+    }
     fn set_longitude_reversed<P: Projection>(&mut self, reversed: bool) {
         /*if reversed {
             self.gl.cull_face(WebGl2RenderingContext::BACK);
@@ -659,9 +661,12 @@ impl App {
         Ok(screen_pos)
     }
 
-    pub fn screen_to_world<P: Projection>(&self, pos: &Vector2<f32>) -> Result<LonLatT<f32>, String> {
-        let model_pos = P::screen_to_model_space(pos, &self.camera).ok_or(format!("{:?} is out of projection", pos))?;
-        Ok(model_pos.lonlat())
+    pub fn screen_to_world<P: Projection>(&self, pos: &Vector2<f32>) -> Option<LonLatT<f32>> {
+        if let Some(model_pos) = P::screen_to_model_space(pos, &self.camera) {
+            Some(model_pos.lonlat())
+        } else {
+            None
+        }
     }
 
     pub fn set_center<P: Projection>(&mut self, lonlat: &LonLatT<f32>) {
@@ -846,7 +851,19 @@ impl ProjectionType {
         }
     }
 
-    fn screen_to_world(&self, app: &App, pos: &Vector2<f32>) -> Result<LonLatT<f32>, String> {
+
+    fn get_max_fov(&self, app: &App) -> f32 {
+        match self {
+            ProjectionType::Aitoff => app.get_max_fov::<Aitoff>(),
+            ProjectionType::MollWeide => app.get_max_fov::<Mollweide>(),
+            ProjectionType::Ortho => app.get_max_fov::<Orthographic>(),
+            ProjectionType::Arc => app.get_max_fov::<AzimuthalEquidistant>(),
+            ProjectionType::Gnomonic => app.get_max_fov::<Gnomonic>(),
+            ProjectionType::Mercator => app.get_max_fov::<Mercator>(),
+        }
+    }
+
+    fn screen_to_world(&self, app: &App, pos: &Vector2<f32>) -> Option<LonLatT<f32>> {
         match self {
             ProjectionType::Aitoff => app.screen_to_world::<Aitoff>(pos),
             ProjectionType::MollWeide => app.screen_to_world::<Mollweide>(pos),
@@ -1375,13 +1392,15 @@ impl WebClient {
     }
 
     #[wasm_bindgen(js_name = screenToWorld)]
-    pub fn screen_to_world(&self, pos_x: f32, pos_y: f32) -> Result<Box<[f32]>, JsValue> {
-        let lonlat = self.projection.screen_to_world(&self.app, &Vector2::new(pos_x, pos_y))?;
+    pub fn screen_to_world(&self, pos_x: f32, pos_y: f32) -> Option<Box<[f32]>> {
+        if let Some(lonlat) = self.projection.screen_to_world(&self.app, &Vector2::new(pos_x, pos_y)) {
+            let lon_deg: ArcDeg<f32> = lonlat.lon().into();
+            let lat_deg: ArcDeg<f32> = lonlat.lat().into();
 
-        let lon_deg: ArcDeg<f32> = lonlat.lon().into();
-        let lat_deg: ArcDeg<f32> = lonlat.lat().into();
-
-        Ok(Box::new([lon_deg.0, lat_deg.0]))
+            Some(Box::new([lon_deg.0, lat_deg.0]))
+        } else {
+            None
+        }
     }
 
     #[wasm_bindgen(js_name = getFieldOfView)]
@@ -1410,12 +1429,11 @@ impl WebClient {
 
         Ok(())
     }
-    
-    #[wasm_bindgen(js_name = setClipZoomFactor)]
-    pub fn set_clip_zoom_factor(&mut self, clip_zoom_factor: f32) -> Result<(), JsValue> {
-        Ok(())
-    }
 
+    #[wasm_bindgen(js_name = getMaxFieldOfView)]
+    pub fn get_max_fov(&mut self) -> f32 {
+        self.projection.get_max_fov(&mut self.app)
+    }
     /// Set directly the center position
     #[wasm_bindgen(js_name = getCenter)]
     pub fn get_center(&self) -> Result<Box<[f32]>, JsValue> {
diff --git a/src/render/src/renderable/image_survey.rs b/src/render/src/renderable/image_survey.rs
index 017e7768..bb7c331f 100644
--- a/src/render/src/renderable/image_survey.rs
+++ b/src/render/src/renderable/image_survey.rs
@@ -1312,11 +1312,12 @@ impl ImageSurveys {
                 let textures = survey.get_textures_mut();
                 match result {
                     TileResolved::Missing { time_req } => {
-    
+                        let missing = true;
                         let default_image = textures.config().get_black_tile();
-                        textures.push::<Rc<TileArrayBufferImage>>(tile, default_image, time_req);
+                        textures.push::<Rc<TileArrayBufferImage>>(tile, default_image, time_req, missing);
                     },
                     TileResolved::Found { image, time_req } => {
+                        let missing = false;
                         match image {
                             RetrievedImageType::FITSImage { image, metadata } => {
                                 // Update the metadata found in the header of the
@@ -1328,13 +1329,13 @@ impl ImageSurveys {
                                 textures.config.scale = metadata.bscale;
                                 textures.config.offset = metadata.bzero;
                                 // Update the blank textures
-                                textures.config.set_black_tile_value(metadata.bscale*blank + metadata.bzero);
+                                textures.config.set_black_tile_value(blank);
     
-                                textures.push::<TileArrayBufferImage>(tile, image, time_req);
+                                textures.push::<TileArrayBufferImage>(tile, image, time_req, missing);
                             },
                             RetrievedImageType::CompressedImage { image } => {
     
-                                textures.push::<TileHTMLImage>(tile, image, time_req);
+                                textures.push::<TileHTMLImage>(tile, image, time_req, missing);
                             }
                         }
                     }
diff --git a/src/render/src/shaders/hips/color_i.glsl b/src/render/src/shaders/hips/color_i.glsl
index 9ecde68a..a33dd7d9 100644
--- a/src/render/src/shaders/hips/color_i.glsl
+++ b/src/render/src/shaders/hips/color_i.glsl
@@ -46,10 +46,6 @@ float get_grayscale_from_texture(vec3 UV) {
 
     float x = get_pixels(uv);
 
-    /*if (x == blank) {
-        return transparent;
-    }*/
-
     float alpha = x * scale + offset;
     float h = transfer_func(H, alpha, min_value, max_value);
 
diff --git a/src/render/src/shaders/hips/raytracer/color.frag b/src/render/src/shaders/hips/raytracer/color.frag
index 3d977332..a8d7de92 100644
--- a/src/render/src/shaders/hips/raytracer/color.frag
+++ b/src/render/src/shaders/hips/raytracer/color.frag
@@ -16,6 +16,7 @@ struct Tile {
     int uniq; // Healpix cell
     int texture_idx; // Index in the texture buffer
     float start_time; // Absolute time that the load has been done in ms
+    int missing;
 };
 
 uniform int current_depth;
@@ -65,16 +66,20 @@ TileColor get_tile_color(vec3 pos, int depth) {
         if (uniq == textures_tiles[i].uniq) {
             Tile tile = textures_tiles[i];
 
-            int idx_texture = tile.texture_idx >> 6;
-            int off = tile.texture_idx % 64;
-            float idx_row = float(off >> 3); // in [0; 7]
-            float idx_col = float(off % 8); // in [0; 7]
+            if (tile.empty == 1) {
+                return TileColor(tile, vec3(0.0), true);
+            } else {
+                int idx_texture = tile.texture_idx >> 6;
+                int off = tile.texture_idx % 64;
+                float idx_row = float(off >> 3); // in [0; 7]
+                float idx_col = float(off % 8); // in [0; 7]
 
-            vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
-            vec3 UV = vec3(offset, float(idx_texture));
+                vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
+                vec3 UV = vec3(offset, float(idx_texture));
 
-            vec3 color = get_color_from_texture(UV).rgb;
-            return TileColor(tile, color, true);
+                vec3 color = get_color_from_texture(UV).rgb;
+                return TileColor(tile, color, true);
+            }
         } else if (uniq < textures_tiles[i].uniq) {
             // go to left
             b = i - 1;
diff --git a/src/render/src/shaders/hips/raytracer/grayscale_to_color.frag b/src/render/src/shaders/hips/raytracer/grayscale_to_color.frag
index 05dacedb..98f01105 100644
--- a/src/render/src/shaders/hips/raytracer/grayscale_to_color.frag
+++ b/src/render/src/shaders/hips/raytracer/grayscale_to_color.frag
@@ -15,6 +15,7 @@ struct Tile {
     int uniq; // Healpix cell
     int texture_idx; // Index in the texture buffer
     float start_time; // Absolute time that the load has been done in ms
+    int empty;
 };
 
 uniform int current_depth;
@@ -67,17 +68,21 @@ TileColor get_tile_color(vec3 pos, int depth) {
         if (uniq == textures_tiles[i].uniq) {
             Tile tile = textures_tiles[i];
 
-            int idx_texture = tile.texture_idx >> 6;
-            int off = tile.texture_idx % 64;
-            float idx_row = float(off >> 3); // in [0; 7]
-            float idx_col = float(off % 8); // in [0; 7]
+            if (tile.empty == 1) {
+                return TileColor(tile, vec3(0.0), true);
+            } else {
+                int idx_texture = tile.texture_idx >> 6;
+                int off = tile.texture_idx % 64;
+                float idx_row = float(off >> 3); // in [0; 7]
+                float idx_col = float(off % 8); // in [0; 7]
 
-            vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
-            vec3 UV = vec3(offset, float(idx_texture));
+                vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
+                vec3 UV = vec3(offset, float(idx_texture));
 
-            vec3 color = K * C * get_grayscale_from_texture(UV);
+                vec3 color = K * C * get_grayscale_from_texture(UV);
 
-            return TileColor(tile, color, true);
+                return TileColor(tile, color, true);
+            }
         } else if (uniq < textures_tiles[i].uniq) {
             // go to left
             b = i - 1;
@@ -89,7 +94,7 @@ TileColor get_tile_color(vec3 pos, int depth) {
     }
 
     // code unreachable
-    Tile empty = Tile(0, -1, current_time);
+    Tile empty = Tile(0, -1, current_time, 1);
     return TileColor(empty, vec3(0.f), false);
 }
 
diff --git a/src/render/src/shaders/hips/raytracer/grayscale_to_color_i.frag b/src/render/src/shaders/hips/raytracer/grayscale_to_color_i.frag
index c90faac1..95f6ba79 100644
--- a/src/render/src/shaders/hips/raytracer/grayscale_to_color_i.frag
+++ b/src/render/src/shaders/hips/raytracer/grayscale_to_color_i.frag
@@ -15,6 +15,7 @@ struct Tile {
     int uniq; // Healpix cell
     int texture_idx; // Index in the texture buffer
     float start_time; // Absolute time that the load has been done in ms
+    int empty;
 };
 
 uniform int current_depth;
@@ -67,17 +68,20 @@ TileColor get_tile_color(vec3 pos, int depth) {
         if (uniq == textures_tiles[i].uniq) {
             Tile tile = textures_tiles[i];
 
-            int idx_texture = tile.texture_idx >> 6;
-            int off = tile.texture_idx % 64;
-            float idx_row = float(off >> 3); // in [0; 7]
-            float idx_col = float(off % 8); // in [0; 7]
+            if (tile.empty == 1) {
+                return TileColor(tile, vec3(0.0), true);
+            } else {
+                int idx_texture = tile.texture_idx >> 6;
+                int off = tile.texture_idx % 64;
+                float idx_row = float(off >> 3); // in [0; 7]
+                float idx_col = float(off % 8); // in [0; 7]
 
-            vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
-            vec3 UV = vec3(offset, float(idx_texture));
+                vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
+                vec3 UV = vec3(offset, float(idx_texture));
 
-            vec3 color = K * C * get_grayscale_from_texture(UV);
-
-            return TileColor(tile, color, true);
+                vec3 color = K * C * get_grayscale_from_texture(UV);
+                return TileColor(tile, color, true);
+            }
         } else if (uniq < textures_tiles[i].uniq) {
             // go to left
             b = i - 1;
@@ -89,8 +93,8 @@ TileColor get_tile_color(vec3 pos, int depth) {
     }
 
     // code unreachable
-    Tile empty = Tile(0, -1, current_time);
-    return TileColor(empty, vec3(0.f), false);
+    Tile empty = Tile(0, -1, current_time, 1);
+    return TileColor(empty, vec3(0.0, 0.0, 1.0), false);
 }
 
 const float duration = 500.f; // 500ms
diff --git a/src/render/src/shaders/hips/raytracer/grayscale_to_colormap.frag b/src/render/src/shaders/hips/raytracer/grayscale_to_colormap.frag
index 559c93c8..81a1bd0a 100644
--- a/src/render/src/shaders/hips/raytracer/grayscale_to_colormap.frag
+++ b/src/render/src/shaders/hips/raytracer/grayscale_to_colormap.frag
@@ -15,6 +15,7 @@ struct Tile {
     int uniq; // Healpix cell
     int texture_idx; // Index in the texture buffer
     float start_time; // Absolute time that the load has been done in ms
+    int empty;
 };
 
 uniform int current_depth;
@@ -61,18 +62,21 @@ TileColor get_tile_color(vec3 pos, int depth) {
     for(int step = 0; step < h; step++) {
         if (uniq == textures_tiles[i].uniq) {
             Tile tile = textures_tiles[i];
+            if (tile.empty == 1) {
+                return TileColor(tile, vec3(0.0), true);
+            } else {
+                int idx_texture = tile.texture_idx >> 6;
+                int off = tile.texture_idx % 64;
+                float idx_row = float(off >> 3); // in [0; 7]
+                float idx_col = float(off % 8); // in [0; 7]
 
-            int idx_texture = tile.texture_idx >> 6;
-            int off = tile.texture_idx % 64;
-            float idx_row = float(off >> 3); // in [0; 7]
-            float idx_col = float(off % 8); // in [0; 7]
+                vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
+                vec3 UV = vec3(offset, float(idx_texture));
 
-            vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
-            vec3 UV = vec3(offset, float(idx_texture));
+                vec3 color = colormap_f(get_grayscale_from_texture(UV)).rgb;
 
-            vec3 color = colormap_f(get_grayscale_from_texture(UV)).rgb;
-
-            return TileColor(tile, color, true);
+                return TileColor(tile, color, true);
+            }
         } else if (uniq < textures_tiles[i].uniq) {
             // go to left
             b = i - 1;
@@ -84,7 +88,7 @@ TileColor get_tile_color(vec3 pos, int depth) {
     }
 
     // code unreachable
-    Tile empty = Tile(0, -1, current_time);
+    Tile empty = Tile(0, -1, current_time, 1);
     return TileColor(empty, vec3(0.f), false);
 }
 
diff --git a/src/render/src/shaders/hips/raytracer/grayscale_to_colormap_i.frag b/src/render/src/shaders/hips/raytracer/grayscale_to_colormap_i.frag
index ca0e76a2..e42229bf 100644
--- a/src/render/src/shaders/hips/raytracer/grayscale_to_colormap_i.frag
+++ b/src/render/src/shaders/hips/raytracer/grayscale_to_colormap_i.frag
@@ -15,6 +15,7 @@ struct Tile {
     int uniq; // Healpix cell
     int texture_idx; // Index in the texture buffer
     float start_time; // Absolute time that the load has been done in ms
+    int empty;
 };
 
 uniform int current_depth;
@@ -61,18 +62,21 @@ TileColor get_tile_color(vec3 pos, int depth) {
     for(int step = 0; step < h; step++) {
         if (uniq == textures_tiles[i].uniq) {
             Tile tile = textures_tiles[i];
+            if (tile.empty == 1) {
+                return TileColor(tile, vec3(0.0), true);
+            } else {
+                int idx_texture = tile.texture_idx >> 6;
+                int off = tile.texture_idx % 64;
+                float idx_row = float(off >> 3); // in [0; 7]
+                float idx_col = float(off % 8); // in [0; 7]
 
-            int idx_texture = tile.texture_idx >> 6;
-            int off = tile.texture_idx % 64;
-            float idx_row = float(off >> 3); // in [0; 7]
-            float idx_col = float(off % 8); // in [0; 7]
+                vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
+                vec3 UV = vec3(offset, float(idx_texture));
 
-            vec2 offset = (vec2(idx_col, idx_row) + uv)/8.f;
-            vec3 UV = vec3(offset, float(idx_texture));
+                vec3 color = colormap_f(get_grayscale_from_texture(UV)).rgb;
 
-            vec3 color = colormap_f(get_grayscale_from_texture(UV)).rgb;
-
-            return TileColor(tile, color, true);
+                return TileColor(tile, color, true);
+            }
         } else if (uniq < textures_tiles[i].uniq) {
             // go to left
             b = i - 1;
@@ -84,7 +88,7 @@ TileColor get_tile_color(vec3 pos, int depth) {
     }
 
     // code unreachable
-    Tile empty = Tile(0, -1, current_time);
+    Tile empty = Tile(0, -1, current_time, 1);
     return TileColor(empty, vec3(0.f), false);
 }