Sign in to follow this  
Ray Proudfoot

No amateur astronomers on the ACES team then!

Recommended Posts

I was really hopeful that FSX would finally resolve a really old problem. That of stars showing whilst the sun is above the horizon. The only bright objects visible at sunset are the moon and Venus. You won't see any stars until 20-30 mins later and even then only in the tropics where twilight is very short.Sadly it couldn't be done or perhaps wouldn't be done. It's a shame really because in many other respects the skies look so much more realistic than in FS9.I'd really like to hear from someone on the ACES team as to whether this inaccuracy was discussed.I live in hope that before I pop my clogs there will be a version of FS that addresses this anomaly.

Share this post


Link to post
Share on other sites
Help AVSIM continue to serve you!
Please donate today!

Yes it is rather unrealistic (maybe it can be changed somehow ?). It would be nice to have the brighter stars show first too but I find the apparent brightness difference amongst stars of various magnitudes isn't well depicted (perhaps also a limitation of me having an LCD monitor at 1024x768) so that stars like Vega, Sirius, Arcturus, Antares etc don't have the same impact as in real life.I also find the moon is not very good in FSX... I must find a new moon replacement.

Share this post


Link to post
Share on other sites

It might not fix this particular problem, but look for "autostarx.zip" in the AVSIM file library.File Description:AutoStar is a program that allows new features to be added to the night sky. It adds the brighter planets in the correct position for any date. Optionally it can add comets, images or user objects such as a lunar eclipse or Messier objects. The program can import the SAO star catalogue, thus allowing the number of background stars to be significantly increased. Filename: autostarx.zip License: Freeware Added: 18th December 2006 Downloads: 4471 Author: Chris Wright Size: 714kb

Share this post


Link to post
Share on other sites

Hi,The definitions of the various stages of darkness are very well described in this Wiki article on Twilight. http://en.wikipedia.org/wiki/TwilightGiven that MS have programmed the sunrise and sunset times for the entire planet it shouldn't be difficult to show stars and planets of various magnitude when certain times have been reached.For example, Venus and Jupiter could become visible at Civil Twilight; stars down to magnitude 2 could become visible when Nautical Twilight is reached and the remaining stars when Astronomical Twilight is reached.All these points can be derived from the time of sunset so it seems a pretty simple change to make. Obviously the reverse would need to happen before sunrise.Although it might seem a bit picky given the realism of the scenery it's small things like this that can make or break the illusion of realism.I know the ACES team read thse pages so how about a comment please chaps?I agree that LCDs aren't as good as CRTs in displaying different brightnesses. But at least they are sharper :-)Cheers,

Share this post


Link to post
Share on other sites

Hi Chris,Although you're correct in saying it won't resolve this problem that offering sounds really good. Nice to see it's had over 4000 downloads.Thanks.

Share this post


Link to post
Share on other sites

In terms of correctly showing brighter stars, FSX represents a *huge* advance over FS9. In FS9 the total brightness dynamic range was limited to just 3:1. In FSX, stars are shown with full 24 bit colour which means, for a white star, the dynamic range is now 256:1, an enormous improvement. However, the default brightness assignments still have a small dynamic range.My AutoStar program addresses this (thanks for the plug, dswo!) First, when creating a new star set the dynamic range can be specified so you can choose how much brighter bright stars will appear. In addition, brighter stars will be created from a small group of up to 16 stars, thus effectively multiplying the dynamic range by 16. The default star set provided with the program has a larger dynamic range than the default, and also slightly stronger colours. But you can play around with the brightness and dynamic range settings to get the balance you want.By choosing a low brightness and high dynamic range setting, only the brighter stars would appear, which might be appropriate for early dusk. A zero brightness setting should mean that no stars show at all, which would be correct if the sun is still above the horizon. I've noticed that in several games the stars appear together with the sun, which is not very realistic!Finally, you can use the user objects feature to place your own image of the moon in the sky.Of course, another option would be to replace the default bitmaps with improved ones.There is one feature I might get around to adding: to reduce the number of stars close to the horizon.Best regards, Chris

Share this post


Link to post
Share on other sites

Now we need to stopped the stars showing in front of the moon !! Only noticed it the other day.

Share this post


Link to post
Share on other sites

Hi, all.Im not in familiar waters here.. But my guess is stars in FSX is treated like an effect or a certain *.bgl file triggered by time and/or season. It would help a lot if stars did not show until the "Time of day" or season was "Night". To do this you need to change som variables within the FSX code. :-sun1

Share this post


Link to post
Share on other sites

Hi Chris,I've downloaded but not yet installed your program. Thanks for creating it.If different brightness and dynamic range values can make stars appear or disappear then if the program ran as a dll within FSX it might be possible to control how bright they appear depending on the time.I appreciate this is easier said than done but if it could be achieved then the problem of stars beng visible with the sun above the horizon could be eliminated.Cheers,

Share this post


Link to post
Share on other sites

Hi Scandi,The stars are contained in a file named stars.dat, not a BGL.As Chris has said by changing their brightness and dynamic range they can be made to appear or disappear.Ultimately it would need a change of the source code but workarounds are always possible. You just need the knowledge and desire.

Share this post


Link to post
Share on other sites

Ray, AutoStar works by writing a new version of stars.dat. As FSX loads this file on startup it probably isn't possible to change the stars without exiting FSX.However, I'm not very familiar with the inner workings of FSX, but I wonder if anyone knows whether there might be FSX system calls that tell it to reload specific data? If so, then something might be done, in fact it would open up some interesting possibilities....I just looked over the program. If you want to play with the brightness and dynamic range settings, then it is necessary to import the SAO star catalog. It's pretty easy and there are full instructions in the manual. To summarise: 1. Download the catalog file and for simplicity rename it to SAO.dat (the address is given in the manual). 2. Decide the limiting magnitude (e.g. 7.0) and import the file (input file would be SAO.dat and output file could be SAO70.dat). You probably won't need to run this again. 3. Now you'll run CONVERT STARS. Set Source file to SAO70.dat. 1 and 300 are good values for Colour strength and Brightness settings. Exponent sets the dynamic range and can have values ranging from zero to 2.5. Zero will create stars all with the same brightness - not very useful. 2.5 will give a 'natural' dynamic range i.e. pixel brightness corresponds to the actual magnitude. However, displays will probably not cope with this (faint stars would probably be so faint as to be invisible). The default value is 1.5. By increasing this (e.g. 2.8) you will increase the dynamic range. 4. Finally click on Make stars! to create the stars.dat file and run FSX. If you enable Show circles you should see the celestial circles in FSX. This is a good test as it covers the entire sky.Have fun and let me know if any problems/questions.Best regards, Chris

Share this post


Link to post
Share on other sites

just wanted to jump in and thank you Chris for your work, the autostar program is great! Have not had a chance to try the FSX version yet but I still enjoy your FS9 version! Your work is much appreciated

Share this post


Link to post
Share on other sites

Alex, thanks for those kind words. You'll find the FSX version is a big improvement with many new features. For example, as FSX displays stars in full 24 bit colour, images such as comets are now fully photorealistic.Best regards, ChrisP.S. it's available in the Avsim library, but it's also available here: http://www.kline.demon.co.uk/AutoStarX.zip I'm pretty sure it's the same version as in the library.

Share this post


Link to post
Share on other sites

Hi Chris,Thanks for the background and suggested settings. I'll install the program over the weekend and come back with my comments.Cheers,

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this