Experimental Observing Simulator

[Jim Smith]

I have been working on a web page to allow new stargazers to find out what they can expect to see with different optical instruments. I think long exposure photos can be very misleading for newcomers.

I have, for now, put version 1 on a free web hosting site here... https://realsky.infinityfreeapp.com
I would be grateful if anyone with a few minutes to spare could take a look and let me know what they think. I think the page is fairly self explanatory.

I'm particularly interested in any technical problems with the page and whether or not you think the images reasonably correctly represent live views through the specified instruments.

Thanks in advance. Jim

[RobertI]

Very nice idea, I think it’s pretty good as a rough guide for a newbie to understand what they can see. A couple of comments - I think Andromeda is much more extensive when viewed through 10x50s, it was spread across a large part of the FOV in my 10x50s recently - the other comment is that it might be worth giving a bit more information about what is a “fairly dark sky” - perhaps the description relevant to Bortle 4 might be appropriate. I viewed on an iPad and worked fine. 

[Sunshine]

This is great, I love it! i have tried several combinations and find it it very accurate to the apertures and types of scope I have.

[Ags]

It is a nice idea but I imagine everyone will see things slightly differently. From a dark site M31 filled the view in 16x50 binoculars, while it is a small smudge in any optic from a light polluted location. The double cluster on the other hand is a lot more showy to my eyes even from a city and in a small refractor.

[Nyctimene]

Good idea. A (perhaps minor) problem might be the colours, especially when choosing the larger aperture settings. Whilst stars may appear in different colours, almost all DSOs, except a few planetary nebulas, will just show shades of grey. Don't know how to solve this problem - perhaps turning down the colour saturation, depending on the aperture?

Stephan

Edited Tuesday at 07:58 by Nyctimene

[PeterC65]

Just tried it on an Android tablet. It works fine mostly. Sometimes I'm not getting an image appearing and need to switch to a different combination though. I found the highlight and arrow a bit confusing as the highlight remains only on the last selected item suggesting that is the indicator of selection whereas it is actually the arrow.

I think this is a great idea and very useful for newcomers to the hobby. Checking the predictions for my scopes, 80mm, 150mm, 200mm, I thought they were accurate for what I can see from my Bortle 4 location.

 

Edited Tuesday at 08:39 by PeterC65

[Astronomist]

I reckon this is pretty accurate for a bottle 4 sky, well done! Would it be possible to add a light pollution adjustment as well, or would that be a lot of work?

 

[bosun21]

2 minutes ago, Astronomist said:

I reckon this is pretty accurate for a bottle 4 sky, well done! Would it be possible to add a light pollution adjustment as well, or would that be a lot of work?

 

That's what I was thinking also. Perhaps a sliding scale for the bortle reading of your sky.

[vlaiv]

Maybe make images black and white instead of in color - as you can't see color (except for the stars).

In 100mm telescope, just the other day, I was able to spot longer extent of the galaxy - but there was no such prominent core.

[bosun21]

3 minutes ago, vlaiv said:

as you can't see color (except for the stars).

And some planetary nebula and of course the planets, but yes the rest is in monotone.

[vlaiv]

I have another very technical advice - not sure if it will be helpful as I'm not sure what your approach is.

Maybe try to get raw data instead of processed data and convert it to XYZ color space. Make sure you add enough background signal depending on SQM reading you want to achieve (in relation to magnitude of the target parts).

Then use CIECAM02 color appearance model to get adjustment from observing conditions to normal viewing conditions for sRGB color space and finally convert transformed XYZ coordinates to sRGB color space.

I'm not 100% sure that it will work, or how well it will work to simulate - but it is the best "scientific" approach that we now have to try to simulate observing conditions.

[Zermelo]

I've just looked at the Newt 150mm option  on my tablet. I used to live in a mid B4 area, and I think all three objects chime well with my recollections, on a dark evening. Of the three, perhaps the Dumbbell is the most optimistic, though I did see the shape regularly. Also, my eyes are on the wrong side of 21 by some distance.

I expect that this is an undertaking where you can get some useful results with a reasonable effort, but once you start to get very scientific about it, then it could get complicated quite quickly?

I think it's a useful addition to the "managing expectations" arena, especially with a few more objects. Perhaps add a link in here? -

 

[Ratlet]

Looks good to me.  I think the 250mm and 150mm Newtonian are both pretty much spot on.  Given how well they are I'm tempted to try on Andromeda again for seeing some banding.  I've never seen it, but I'm now thinking that it's perhaps a lack of experience on my part.  I think the 150mm is pretty close to 130mm as well as they both look broadly similar to my memory of what they looked like from here.

I'm also Bortle 4 so it seems that is what they are normalised for?

[Emperor!Takahashi!]

Great work! I think this will be such a useful tool. Thank you for creating it.

[Jim Smith]

Thanks to everyone for your comments and suggestions. I hope to add a few more objects when clear skies allow. I'm also going to investigate preloading the images so that the view is refreshed more quickly. My skies are Bortle 4 here so that has influenced my perception of what looks right. 

[cajen2]

Great idea, I think. Perhaps a planet or two would be interesting. Jupiter would be my choice...

[Ratlet]

23 minutes ago, cajen2 said:

Great idea, I think. Perhaps a planet or two would be interesting. Jupiter would be my choice...

Planets would be really useful, but that something where seeing will have a big effect.  Could potentially be 'easy' to implement though, maybe a slider to apply a blur.

I think that if you were doing planets you have to account for seeing.  I can vividly recall seeing Jupiter with good seeing for the first time.  I swore and laughed and if you told me it could look that good before I would have called you a liar.

 

[cajen2]

44 minutes ago, Ratlet said:

Planets would be really useful, but that something where seeing will have a big effect.  Could potentially be 'easy' to implement though, maybe a slider to apply a blur.

I think that if you were doing planets you have to account for seeing.  I can vividly recall seeing Jupiter with good seeing for the first time.  I swore and laughed and if you told me it could look that good before I would have called you a liar.

 

Oh, yes, I agree. Nevertheless,  the app could give an idea of size and possible features.

[AstroMuni]

On 30/09/2024 at 21:01, Jim Smith said:

I have been working on a web page to allow new stargazers to find out what they can expect to see with different optical instruments. I think long exposure photos can be very misleading for newcomers.

This is so cool. Love it.

Is it just the 3 objects at the moment?

Suggestions:

- As others have said perhaps a Bortle sky selection would help determine what they might see.

- Have you seen this page? May give you a few more ideas https://www.stelvision.com/astro/telescope-simulator/

[Jim Smith]

45 minutes ago, AstroMuni said:

Is it just the 3 objects at the moment?

Suggestions:

- As others have said perhaps a Bortle sky selection would help determine what they might see.

- Have you seen this page? May give you a few more ideas https://www.stelvision.com/astro/telescope-simulator/

Yes, just three...but hopefully more soon if weather allows.

I'm thinking about how to do a "light pollution" control.

Thanks for the Stelvision link. That is interesting to see.

Edited yesterday at 15:32 by Jim Smith
Addenda

[JAC51]

Thank you I think this is a great idea and very helpful in giving people realistic expectation’s.

Over the weekend I was looking at the Dumbell with a 10” Dob and a 5” refractor under bortle 4 skies. The views are similar to your simulation in the extent of the nebulae. I would though agree to desaturating the colour.

[Jim Smith]

2 hours ago, JAC51 said:

I would though agree to desaturating the colour.

I have already desaturated the nebula colour by 75%. I'm thinking now that perhaps I need to remove all colour.

[JAC51]

For colour on deep sky objects, apart from Stars, the only colours I remember seeing are just a hint of blue in Pleiades and  green in M42 with a 10”  reflector.

Now though my eyes are older.

[Jim Smith]

Version 2 is now up.

Nebula colour reduced further and new "Sky Brightness" slider added.

Slider appears not to work on Safari! I think Chrome, Edge and Firefox are OK.

[Astronomist]

I'd say the LP slider works very well for Andromeda and the double cluster, but not so much for the dumbell. I think the view seems to improve at first as you increase the brightness. I suppose it's pretty hard to increase the background brightness without affecting the nebula too though, so maybe not something that can be dealt with.  

When this is finished the mods should sticky it at the top of the 'getting started with observing' forum!