Leo Triplet Attempt (kinda.....maybe?)

[Astro Waves]

Hiya,

So first clear(ish) night this month for me. Still new to the whole AP so just raring to go when ever I can. Been looking at easy targets as I'm also shooting on a Redcat with a canon 750D so probably got about 380mm-ish on it which is nice combined with a iOptron SKyguider Pro (shooting unguided) with a tripod but having no problem getting good 180 second subs. So I thought I'd have ago at the Leo Triplet, managed to get about 30/40 minutes of data. Had a quick go at processing but, no idea if I was even in the right place. I spent a while taking test shots and trying to line up also kinda by sight where I thought I was.

I guess the main take away thing I'm asking is how do you really know if you're in the right place when framing up a target? I spent a while looking at other pictures and stellarium to try and match some star patterns with it but I'm just finding it difficult to know if I'm even getting any where remotely close and that kinda goes for other targets as well as a lot of the time you have to wait till the processing part to really stretch the data, I'd love to have a go at the heart and soul nebula but literally wouldn't have any idea if I would even be framing it up. Is a lot of this just something that comes with time and getting to understand the night sky more? Probably helps when its properly clear as well but any advice is more than welcome. 

[symmetal]

4 hours ago, Astro Waves said:

I guess the main take away thing I'm asking is how do you really know if you're in the right place when framing up a target?

The easiest way is to use plate solving software to analyze the star patterns in a test image you've taken and tell you the RA and Dec coordinates of the centre of the image and also the angle of the camera compared to the celestial equator.

Most image acquisition incorporates the ability to use plate solving software so makes it easier to use. Astro Photography Tool is a low cost but powerful program commonly used with DSLRs, along with other astro cameras.

The documention on APT's Point Craft gives instruction on how to install the plate solving software and use it. ASTAP should be all you need but you can install all three recommended plate solve programs if you wish.

Higher cost mounts can be automatically moved to point the scope to the coordinates you want by using software like APT to repeatedly plate solve and slew the mount until they match.

With your SkyGuider you'll have to manually move the mount RA and Dec between plate solves to get closer but you'll know how far away you are from your target each time. You can use a higher ISO and say 5 to 10 second images each time to plate solve your way to your target. 🙂

Alan 

[Astro Waves]

Hi Alan,

I'm unable to use Astro Photgrpahy Tool as I'm a Mac user, but might end up getting a cheaper windows computer so I can leave it out with the setup whilst its shooting.

I've had a look into ASTAP and download it as well as the star database but I feel it will take me some time to figure out what's actually going on, as I can't say I'm the most tech savvy person but wanting to give it a go. I've had a look not higher cost mounts but due to moving about a lot and work being intermittent I'm quite reluctant to get a bigger mount until I end up being some where for a longer period of time. I'm assuming you can hook the DSLR up to ASTAP for a live feed so to speak rather than having to take a shot then get the memory card out and downloading the data etc.?

I don't mind having to do things manually at all and actually quite like that aspect of it. 

Thanks for your help.

[Astro Waves]

Been playing around with ASTAP all day and trying to watch tutorials.....I literally I have no idea how it works, its so confusing. Various places and forums state that its great which is good but I feel at such a loss with it. Even the guidance on the actual site doesn't help at all. I'm guess that it will hopefully come with time. 

Edited March 22, 2021 by Astro Waves

[symmetal]

As your DSLR files don't include header information like fits files which gives information on where the scope is believed to be pointing to etc. ASTAP and other plate solvers need a hint on where to start doing a spiral search to find a match which it would get from the fits file. I tried some old DSLR images I had taken a long time ago and ASTAP failed initially to solve. 

If you give a hint on where you think the scope was pointing to after you load your image in ASTAP, by entering approx coords of the Leo Triplet in the green indicated boxes in the first image below, or double clicking in either box and just enter M65 or NCG3623 and it should find the right coords to fill in. Clicking Solve should then work. If it still fails, click on the sigma icon indicated in red, and you get the scary configuration screens as shown in the second image. 🙂

The 'Alignment' tab along the top row should be already selected. In the 'Radius search area' box select a larger radius, up to180 degrees, to widen the search radius. Doing this solved all my old Canon CR2 images OK. It reported the Field Of View (height) selected was wrong but corrected it for the first image. For large images it may be quicker to downsample the image before solving by selecting say 2, in the Downsample box under Tetrahedron detection to the left of the red indicated area. 'Clicking Solve current image' to the right of the red indication should say whether it succeeded in the text field at the bottom. If it did, close the configuration screen and load and solve images on the main ASTAP screen. I also found that selecting 180 degrees search radius, that no hint was required in the green indicated boxes though it took a bit longer to plate solve, so it was effectively 'Blind Solving'.

I hope that helps you out Astro Waves and that it works for you.

As a last resort you can always upload an image to astronomy.net and it will blind solve your image without any hints though it can take quite a while. I'm sure ASTAP will work for you now though. 😀

Edit: Actually, ASTAP is written by han59, a member on this forum so he'll be able to help out if you still have issues. 🙂

I should also add that poorly focused stars or very elongated stars due to tracking errors may cause plate solving to fail, so upload one of your images to the forum if you're still having problems for us to have a look at.

Alan

Edited March 22, 2021 by symmetal

[savcom]

On 22/03/2021 at 17:31, symmetal said:

As your DSLR files don't include header information like fits files which gives information on where the scope is believed to be pointing to etc. ASTAP and other plate solvers need a hint on where to start doing a spiral search to find a match which it would get from the fits file. I tried some old DSLR images I had taken a long time ago and ASTAP failed initially to solve. 

If you give a hint on where you think the scope was pointing to after you load your image in ASTAP, by entering approx coords of the Leo Triplet in the green indicated boxes in the first image below, or double clicking in either box and just enter M65 or NCG3623 and it should find the right coords to fill in. Clicking Solve should then work. If it still fails, click on the sigma icon indicated in red, and you get the scary configuration screens as shown in the second image. 🙂

 

Thank you so much.  This was the clue I needed to start getting images plate solved.  Funnily enough, my scope's polar alignment with its polar scope was out and I discovered this by failing to shot the Leo Triplet.  I wanted to plate-solve the image to see where I was actually pointing at.

[symmetal]

Glad you found it useful savcom. 😀

Alan