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Finding Objects

astrophotography beginner eyepieces imaging
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#1 Rsquared

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Posted 01 June 2020 - 05:32 PM

Hey everyone, I just started astrophotography and was wondering how you guys find objects without a guide scope.  I am using a Canon EOS Rebel T7i, 300mm lens, Star Adventurer, and a standard tripod.  Anyway, I tried to get the Iris Nebula last night, and think I might have got it, but in my shots (even stacked) the subject looks just like a blue star even at 300 mm zoom and 60 second subs.  I'm not sure if this is just a limitation of my equipment or I'm simply looking at the nearby star Alfirk instead.  Essentially, I use stellarium to view what the night sky should look like surrounding the iris nebula, and attempt to find it using quick 5-second exposures which appear on the camera's screen.  Is this star in the center the IRIS Nebula?  Also, how do you guys find objects w/out guiding gear? Anyway, I'd appreciate any feedback as I am very new to this hobby.

 

Is there a software which allows you to upload an image and will tell you which part of the sky you are looking at?

 

Also, if anyone has any good suggestions for cool objects to photograph possible using my gear, I'd love to hear them.

 

Thanks!

 

screenshot.jpg


Edited by Rsquared, 01 June 2020 - 05:35 PM.


#2 nimitz69

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Posted 01 June 2020 - 05:35 PM

Guide scopes and cameras do not help you find targets. They are to do precision tracking so you can do long duration exposures in excess of 30 secs up to many minutes

The best way to find objects is by plate solving (requires a PC and any number of free plate solving programs) or if you have a. GOTO mount you can use that and if you’re really a gluten for punishment you can try starhopping....smile.gif

Edited by nimitz69, 01 June 2020 - 05:36 PM.

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#3 Peregrinatum

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Posted 01 June 2020 - 05:36 PM

platesolving, it's astro magical


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#4 james7ca

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Posted 01 June 2020 - 06:00 PM

You can "solve" for the location of an astrophotograph and produced a labeled image using Astrometry.net. Usually takes a few minutes after you upload your image.

 

However, there are other (and faster) ways to platesolve an image, but some of those require that you install software on your PC (Astrometry.net is a blind solver that works from within your web browser and it's free).

 

Below is the solution of your image as produced by Astrometry.net and it looks like the Iris Nebula was out of your field (you were centered near the constellation Draco and about seven degrees away from the Iris nebula).

Attached Thumbnails

  • Astrometry Plate Solve.jpg

Edited by james7ca, 01 June 2020 - 06:04 PM.

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#5 Rsquared

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Posted 01 June 2020 - 07:53 PM

You can "solve" for the location of an astrophotograph and produced a labeled image using Astrometry.net. Usually takes a few minutes after you upload your image.

 

However, there are other (and faster) ways to platesolve an image, but some of those require that you install software on your PC (Astrometry.net is a blind solver that works from within your web browser and it's free).

 

Below is the solution of your image as produced by Astrometry.net and it looks like the Iris Nebula was out of your field (you were centered near the constellation Draco and about seven degrees away from the Iris nebula).

Thank you so much! I had never heard of plate solving before!



#6 Alex McConahay

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Posted 01 June 2020 - 07:57 PM

What software do you use to grab your images? Many simple astroimaging programs (session managers) have this as one of their primary functions. 

 

Alex


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#7 SilverLitz

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Posted 02 June 2020 - 07:52 AM

Later in the summer/fall, M31 should be a good, big, and bright target for you as it frames up very good at 300mm and APS-C.

 

Before that, you can try M16 (Eagle) and NGC7000 (North America).  These are not any where as bright, and being nebulas, they have a lot of Ha, so they are MUCH better with a mono camera and NB filters, but their size is large enough not to be a speck in a big star field with a short FL. 


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#8 Rsquared

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Posted 02 June 2020 - 09:42 AM

What software do you use to grab your images? Many simple astroimaging programs (session managers) have this as one of their primary functions. 

 

Alex

Hey Alex, I'm just using my Canon EOS software to take pictures remotely.  Do you have any suggestions for imaging software? Thanks



#9 DubbelDerp

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Posted 02 June 2020 - 09:54 AM

I just shoot off a Skyguider Pro with a DSLR and lens, so platesolving really isn't an option for me unless I wanted to run back and forth between my setup and the house. What I find to be the best option for my situation is a red-dot sight mounted to the hot shoe adapter on the camera so I can see where it is pointing in conjunction with SkySafari on my phone. I've set up a field-of-view indicator for each of my lens combinations in SkySafari so I can recognize bright stars in or near the target, and use these as my reference for finding an object. You can also star hop with the red dot sight.

 

Once I know I'm in the right area of sky with the red dot sight, I'll take an 8-10 second exposure at high ISO and compare the resulting image to what I see on my phone. Adjust, take another exposure, repeat. These camera trackers are not awesome at fine adjustments, but usually you can be on target in a few minutes. It'll take a little bit of practice, but I think it's a skill worth developing. Just make sure you align the red dot sight with your camera lens while it's getting dark.


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#10 Alex McConahay

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Posted 02 June 2020 - 10:23 AM

>>>>>Do you have any suggestions for imaging software?

 

My suggestion for the long run would be Sequence Generator Pro. But there are many other good packages. I am sure you will get other suggestions. 

 

There was a show on The Astro Imaging Channel that might help you decide: https://youtu.be/0WBfePL23HA

 

Alex


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#11 SilverLitz

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Posted 02 June 2020 - 01:56 PM

I found APT very easy to learn, and I have not gone past the free trial version (limited functionality).  NINA is a new capture SW that many like a lot with a lot of development and functionality, and it is free.  I have heard that NINA is better at AF than APT and SGP.  This is the reason that I have not gone to the higher function paid APT version, as it sounds like it has deficiencies in AF (where I want to go).

 

There is BackyardEOS which is a long term favorite by many, but it only works with Canon DSLR.  I started with my Canon DSLR, but I started with APT, because it has more functionality than BYE, and works with cooled astrocams.  I quickly changed to a cooled, mono astrocam, so skipping BYE was a good decision for me.


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#12 Blackbelt76

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Posted 02 June 2020 - 02:04 PM

Agreed. Astrometry.net is amazing.

I didn't have such a great web site yrs ago to reference.

Although my GoTo mount is pretty good, it really helps me center the image where my 200mm is sharpest..


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#13 Ryou

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Posted 02 June 2020 - 05:06 PM

Definitely take a look at some FoV calculators/throw your scope/camera into things like Stellarium to see the framing and brighter stars you should have. This will help a lot when looking at the subs if you don't want to/can't plate solve. Here is the t7i with a 300mm lens and the Iris Nebula centered in Stellarium:

Iris.jpg

 

As was mentioned a small red dot finder in the hotshoe can help figure out where you are pointing also, and I have heard of people using bright green lasers attached to the lens also. Please be sure check any local laws and regulations, along with airplane flights if you're near an airport, before doing the laser though!

 

It sounds like you are using some form of computer control (I have a t7i myself and know it doesn't have a built in intervalometer) already, so I would highly look into something like Astro Photography Tools, Sequence Generator Pro, etc which can do platesolving. As you've seen, even with a wide field scope, you can easily miss the target. Even with a GoTo mount you could miss the target too depending on various factors! So some form of platesolving really is going to be the best option for finding a target.

 

For the larger targets, especially if you can see details of them in a single sub, it does become easier with widefield scopes to find and frame if you start close by. Andromeda, Heart and Soul, North American, Elephant Trunk, Cygnus Loop/Veil Nebula (east and west veil) are all pretty big so could show up well. However they are all mostly emission nebulae so may or may not be visible in a single sub. One thing you could definitely look at/try for this is Sadr though. This is near the crescent nebula and has a lot of nebulousness in the region.. and Sadr is smack dab in the middle of it basically. Being a fairly bright star you should be able to fairly easily find it hopefully.


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