Jump to content

sgl_imaging_challenge_2021_annual.thumb.jpg.3fc34f695a81b16210333189a3162ac7.jpg

How in the world do I locate targets with the z61?


Recommended Posts

Hello, 

It is 1:10 in the morning right now after having my first go at imaging something with my astrophotography setup. I spent about 3 hours, one getting used to the telescope, and the other two trying to find a target. When I look through my camera at the sky, I see possibly one or two stars that I can use as points of references. Unfortunately though I am having trouble discerning what stars they are. Since I don't know what stars they are and since I am seeing very few, I am a bit confused on how I am supposed to find something to image. I've heard that raising the ISO will allow you to see more stars but that didn't seem to work. Any advice?

My setup consists of the:

Star Adventurer 2i

WO Z61

and the Canon EOS Rebel T2i

Thanks!

Link to comment
Share on other sites

Hello there!

I know the feeling from my first night of trying to frame something, very frustrating burning away valuable imaging time just finding an object 😅 some people advise platesolving which is probably the best way, not got round to doing that myself so wouldn't be able to explain exactly how that works. Plenty of youtube videos on it I'm sure 😀

But I use a red dot finder myself, I find a bright star to focus on anyway, usually deneb or vega at the moment, you should know when these bright stars are on your cameras live view, compared to the less bright surrounding stars, whilst doing that I also align my Red dot finder to that star. That way when it comes to finding your object you just need to know where it lies relative to the stars, take a short exposure when you think you're about right, check and adjust accordingly, can usually get the object framed within 2-3 30 second exposures 😀

Hope this helps 😀

Grant

  • Like 1
Link to comment
Share on other sites

I had exactly the same issue:

You can get a red dot finder that clips on to the hotshoe on the camera. I only found this out in a reply to my own review..worth its weight in gold.

  • Like 1
Link to comment
Share on other sites

In the early days of myself using the star adventurer I used this method. Raise the iso to something like 6400 (although that would depend on your sky conditions). Point the scope at an area of sky where you can see a known sky (naked eye). Take a 10 second exposure. Then compare the stars you see on the image with the picture you see on an app such as skysafari (I recommend this one).  You can then match up what you see in your image with what you see in sky safari. It takes some practice but this is what I did to manually find targets to image.

  • Like 1
Link to comment
Share on other sites

Posted (edited)

Hi there,

Apologies, but I don't know how experienced you are with Astronomical Observation so my question is - have you got the book 'Turn Left at Orion'? It doesn't have everything by any stretch of the imagination but it helps you to get started in navigating around the night sky season by season. This is a link to online content:

https://www.cambridge.org/turnleft

I believe a finder scope will also help you.

Stu

Edited by Sabalias
  • Like 1
Link to comment
Share on other sites

One of the sky chart type mobile apps can be very useful such as stellarium, skeye etc

I've found them useful to give me an idea of what I'm looking at, plus they support night modes so can have a red screen to not ruin your night vision

A pair of binoculars can also be handy if you happen to already have a pair as you can sweep around looking for targets quickly

As per the post above, a finderscope would be very useful too, personally find red dots easier (but the whole subject of finders can also be a can of worms ;) )

  • Like 1
Link to comment
Share on other sites

Posted (edited)
2 hours ago, doublevodka said:

One of the sky chart type mobile apps can be very useful such as stellarium, skeye etc

@Scribblecrans +1 to this suggestion. On the topic of red dot finder, I personally prefer using a Telrad.

Another way that would work is if you attach your camera to your computer and use a software like Kstars/Ekos to platesolve. This will then show you on screen exactly where your camera is pointing to.

Edited by AstroMuni
Link to comment
Share on other sites

If youre looking for something very faint then plate solving has worked really well for me. I just use stellarium to find the coordinates of the object i want to look at, then use NINA and ASTAP to plate solve and find what the coordinates are of the stars I am seeing through my telescope and adjust from there. Usually only takes a few minutes to find what Im looking for.

Link to comment
Share on other sites

Hi @Scribblecrans, we all know that feeling but don't give up! It gets easier with experience. 

I agree that plate solving is the gold standard when it comes to accurately positioning your rig on-target for imaging, but I'm not sure if it will work particularly well with the Star Adventurer. It's a game changer for mounts with two axis motors as the PC can control the mount pointing position but I don't think the SA is like that? I've gone fully automated with my imaging equipment. This means that I never need to look up at the sky as the computer does its job - this has advantages of repeatability and accuracy, but it defeats the purpose of the hobby to a certain extent. So much so that I've just bought a cheap and good small scope for observation, while the imaging scope is doing its thing. 

So the last few nights I'm back to the task of manually finding faint targets in fairly bright skies, just like you. I think there are three key steps:

- Be familiar with the sky in the region around your target. Understand what you're looking for, and plan out how you will get there. You will use the technique of Star Hopping to get from a known bright star/asterism to your target. As mentioned above, planetarium software, or books like Turn Right at Orion are almost essential; otherwise you are on a random walk (which can be enjoyable too for a while). 

- Get either a red dot finder (RDF) or a Telrad, to get you in the right general area (this is essential!!!). Your scope has a wide field of view, so once you have located the target in the RDF/Telrad, you can be confident that it is also in the camera fov. Personally I prefer the RDF. 

- Once you're in the right general area, bump up the ISO on your camera and take some test shots. You should be able to recognise star patterns as you're already close to target. This might be easier if you connect to a PC as the bigger screen might show more detail. Again, back to the first point above, if you're not familiar with the area, you won't recognise the patterns. Turn Right at Orion gives you a very good process to work one step at a time from a known point to a target point. Try to be systematic about how you move - if you think it's "5 Dec turns East" but you don't see what you're looking for, retrace your steps "5 Dec turns West" to the last known position and try again. If you go scrolling around looking for something, you'll get lost and have to start from the beginning again.

If you go with a RDF or Telrad, you can align it with the main scope during the day, using a distant tree or chimney.

Finally, here's an interesting post from DPReview that explains a very method that's similar to this.
https://www.dpreview.com/forums/post/62267807

 

  • Like 1
Link to comment
Share on other sites

4 hours ago, Chefgage said:

Take a 10 second exposure. Then compare the stars you see on the image with the picture you see on an app such as skysafari (I recommend this one).  You can then match up what you see in your image with what you see in sky safari. It takes some practice but this is what I did to manually find targets to image.

This is plate solving like they used to do 😁

  • Like 2
Link to comment
Share on other sites

Plate solving can be done with some success, hardest part is the declination because of the lack of powered adjustment there; using a tool like this to set it manually to target will get somewhere near but would need the accuracy latitude in plate solving being quite wide (mine is set to 1200 arcsec or 1/3rd a degree) as the adjustment isn't that precise on the DEC rotator (https://www.astropills.com/blog/declination-setting-circle).

A Star Adventurer 2i connected as an EQMod mount (don't know about the earlier versions) will slew on to target after solving, though with not as tight an accuracy, as mentioned above.  The way I do it on mine with it being coupled to a Raspberry Pi (primarily for guiding), is look up the coordinates of where I'm looking, set the DEC, and then manually input the coordinates in to kstars to initially fix a rough starting point, then capture, solve and sync through EKOS, then back to the manual input but this time issuing a slew command.  It's doable, but as the mount isn't really thought for things like this it does have some quirks compared to a complete EQ mount, and depending on which way around it's implemented can reduce the thing that makes the SA a fun tool, the portability.

Learn how to go about it manually first, then if you feel you need add more frustration to the SA, look in to a plate solving system.

Link to comment
Share on other sites

5 hours ago, The Lazy Astronomer said:

This is plate solving like they used to do 😁

And now I let the asiair do it for me :) Although doing it sort of manually is more satisfying :)

  • Like 1
Link to comment
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
 Share

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.