Astrophotography with or without tracker ?

Messages
183
Name
Liam
Edit My Images
Yes
#1
Hi all,
I’m looking to get into Astrophotography,
And I would like some advice if possible please,
I’d like to use my 300mm lens to avoid getting a dedicated telescope,
I have a 600mm too if this would be even better ?,
Would be used on a Nikon D7500,
Can I get detailed images of Orion, Pleiades and nebula etc...,
I understand I’d have to stack them to get the best detail,
But would I be able to achieve this without a star tracker that attaches to my tripod,
I’ve been looking at the star adventurer mini if this is any good,
But ideally I’d like to try it without the tracker before I lay out the money,
Any help and advice is much appreciated,
Thanks
 
Messages
340
Name
Steven
Edit My Images
No
#2
Hi,

I don't know too much about this as I am just getting my feet wet with it as well. Without a tracker, you will be limited to the length of exposure you can take before you get movement and trailing. There are formulas but lets say 20 seconds or so. From what I've seen, these images of deep sky objects are made up of many stacked exposures, maybe totalling hours in length. That would suggest to me that a tracker mount is essential for this type of photography in order to counteract the movement. The iOptron Skywatcher, and other variants, has a max weight limit of 5kg but it may not work well at that limit. Beyond that you need a dedicated mount. So work out how heavy your gear is and if the Sky Tracker would be sufficient.

Regards...
 
Messages
3,375
Name
Jan
Edit My Images
No
#3
The longer your focal length the less time you have before trailing of the stars becomes an issue (they're not moving - we are). To image the sort of objects you want a tracking mount is essential. A 300mm lens will allow you to fill the frame with a large object like the North American Nebula. A 600mm lens will capture the Pleiades very nicely, or get the Orion Nebula plus the Running Man and a couple of close by star clusters in the same image.Have a look at my Flickr Astronomy album. Some were taken through a scope, some with various lenses. I'm talking using the lenses I mentioned on a crop sensor. I'm not familiar with Nikon so I have no idea if the D7500 is crop or FF. Even using a short lens to take wide field shots of constellations you'll need to track to get the length of exposure to show nebulous patches, clusters etc. As Steven says, pick a tracker that'll carry your heaviest camera/lens combination plus a bit as they're best not worked at their absolute limit. I limit my exposures to 1 min as none of the mounts I use are guided to compensate for any tracking errors I might get at longer exposures. Even with a short lens 1 min would be impossible without the tracking. Deep Sky Stacker can do a decent job of stacking and is free. I use PixInsight, which is specialist software, much more sophisticated than DSS and handles the post processing too. It's not free! I would normally stack at least 30 seperate exposure. For objects like the Orion Nebula or Andromeda Galaxy it helps if you can take a number of different length exposures and HDR combine them (DSS won't do this) to get detail in the bright and the faint areas.
If you get a tracking head you need a sturdy tripod to mount it on, so make sure you have one up to the task. I use a lightweight driven equatorial mount, a lot beefier than a camera tripod but not up to carrying a scope plus camera. It'll carry the camera and 150-600mm lens nicely. The big advantage of a tripod and tracker is portability, which isn't a concern for me but if you need to pop your kit in the back of a car will be for you.
 
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3,375
Name
Jan
Edit My Images
No
#7
The messier 42 and 43, first one in your album
There are 2 of that combination. One was taken with a scope (not mine - my little scope is only for visual), the other was taken with my Sigma 150-600 on my own mount. Both use HDR. For the one taken through the scope was I used our 350D which has had the IR filter removed from the sensor making it better for astrophotography, especially nebulae (and useless for any other sort of photography.........). The one taken through the lens was with my bog standard 550D that I use for everything..
Joel (smr) who's on here produces some great astro stuff using a Star Adventurer tracking mount on a tripod. I'm sure he'd be happy to offer advice if you tag him.
 
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