Anybody using MFT bodies for astrophotography?

Started Oct 8, 2016 | Discussions thread
Astrotripper Veteran Member • Posts: 5,749
Re: Anybody using MFT bodies for astrophotography?

Max Iso wrote:

Astrotripper wrote:

The moon

You can shoot the Moon with any telephoto lens, the longer it is, the better. Here's what 300mm gets you (I'm pretty sure this one is a 1:1 crop). Here's what a cheap 1300mm MAK telescope gets you. And here's what a lot of post-processing can get you (750 newtonian with a 2x Barlow lens and a lot of time spent stacking and stitching). An affordable telescope on a cheap tracking mount will be enough to take amazing photos of the Moon (and Sun , with a proper filter). You can even manage without tracking, but that's inconvenient.

So here is the part im most interested in, although i include the below section of deep space telescope work. I do have a couple questions first (and by the way ty for much info in your post). For either of your telescope shots did you use a field flattener?

No, since I do not own a refractor. My newtonian would definitely benefit from using a coma corrector, but one is not available for it (not sure if there are general purpose ones). And the MAK I have is something like f/13 and I don't think it needs any corrective optics (it's also not particularly impressive in any regard).

One of the things i was told in the AP thread was i will NEED one.

If you are really serious about AP, then yes, as this is the only way you could fully utilize full area of the sensor in your camera. And I guess some telescopes need more corrections than others. I'm out of touch with what's currently on the market, though. But as I wrote, the bigger the sensor, the bigger the need to use corrective optics. With my cheapo SkyWatcher 150/750, I can get acceptable stars within a 1:1 crop that's about 2/3 or 3/4 of the shorter end of the frame. After that, coma starts to kick in. I have not had any experience with refractors to say for sure, but my guess is that the image in the centre should be acceptable even without flattener. But how big that area will be, I don't know.

Does that depend on the telescope, or the type (reflector vs refractor), is it only the cheapest scopes that need it? Is it only the fastest? Considering i haven't really done any AP before i didn't want to spend handfulls of cash up front, i wanted to tip toe in and see if i like it, if i do then i go further. So i was looking at some cheaper scopes ie sub $200 models, as far down as $60.

Don't bother with those cheap toys, you're not gonna get anywhere with those.

Are there no such thing as a decent cheap scope?

Exactly. At least not for any kind of astrophotography. They might be ok for casual visual observations, but AP is way more demanding of the gear.

I can say for sure that your first link of the 300mm lens would not satisfy me.

Yeah, 300mm is a bit short for the Moon. Samyang makes cheap 500mm mirror lenses. If they are as good as my Tokina, that might be worth a try. I think they even make them with T2 mount and offer a teleconverter for them. That could get you to 1000mm relatively cheaply and in relatively small package. But I have no idea about quality.

The 2nd of the 1300 mak was ok but i would like sharper.

The problem with shots from that MAK is that every small air turbulence will show. And it's something like f/13, so you end up using high ISO and shutter speeds might not be fast enough. Also, smaller maks are often very prone to shutter shock and my E-M10 does not have e-shutter. And I was using that MAK mostly on my balcony, so air turbulence was always a problem. As you can see, there's a lot of potential problems

The 3rd was great, would love results like that.

Yeah, that turned out well. But it also required massive effort in post. At 1500mm (750mm with 2x Barlow lens), you can only capture part of the Moon. So I had shot two series of photos. And then, for stacking, I had to split each photo into four smaller ones, since full res images were too big for stacking. So in the end, I get 6 separate stacks and it's time for stitching them together. A massive pain in the a**. That took a whole day to put together. I still have like 300gb of unprocessed material because it's so time consuming.

However, you have a Panasonic camera. And Panasonic cameras have high quality 1:1 sensor crop video (electronic tele converter I think it's called). This might be a much better way to shoot the moon. It will require stitching of course, but you avoid problems with shutter shock or image size limits in stacking software. And most stacking software aimed at processing moon and planets are optimized to work with video files anyway. I always wanted to try this approach, but now when I finally have a Panasonic body, I don't have a telescope to test it with.

My plan is to minimize any vibrations with E shutter and use multiple shots and stacking, maybe eventually getting a tracker if my interest peaks. I also have a shutter remote already for my GX7.

Whatever telescope or mount you get, I really suggest you get a motorized one. It can be a simple one axis motor, just as long as it's there. You would be surprised how fast that Moon flies by your field of view at 1500mm

So i guess the only unknown is the optics of the scopes. I know reflectors are CA free essentially but your 3rd shot was with an achromat if im not mistaken and i saw no CA at all. Maybe you PP'd that out?

I don't remember if I did specific CA removal. I might have enabled auto CA removal when converting RAWs. But in general, I have not had any problems with it, to be honest. When using a barlow lens or the MAK, there is a tiny bit of it, I'm sure, but other stuff (like seeing) is usually a much bigger problem.

I have two main concerns with reflectors. One, i don't like the idea of having to colimate. Im sure i could do it but i prefer less maintenance.

Yeah, collimation is annoying. Especially on cheap telescopes that have very fiddly mirror mountings that make it very hard to fine tune mirror positions. Unfortunately, reflectors can also need collimation, although I always assumed they are properly collimated when leaving the factory. But you'll probably get more useful information from someone who actually used one. Actually, I recommend you head over to cloudynights.com, where I'm sure you will receive much more precise information when it comes to telescope selection.

The 2nd thing is the upside down or reversed thing. If i attach my camera to a reflector, will the image be flipped? I know a refractor works just like a normal lens which i like. TBH i like the idea of a reflector more but these two unknowns are holding me back.

It does not matter at all. You can rotate the camera 360 degrees and set the frame whichever way you want. This is where a fully articulated screen comes in very, very handy.

BTW, here's what my MAK setup looked like .

But i really like the idea of reflectors. They have no CA, they are lighter, you get more aperture for your buck and they have longer FL options. It's just those couple issues i am wondering about.

The downside of reflectors is that they are big and need a solid mount to keep them stable. Catadioptric telescopes, like the MAK I have, are small and offer very long focal lengths at small size, but are slow (usually f/11 and slower) and are pretty much useless for anything other than planets and the Moon (and Sun). And you can look at reflectors as specialized telephoto lenses

As with anything, there's not a single silver bullet solution. It's like with camera lenses. Pick any three important properties, and you can only have two at the same time

One more advice. Buy second-hand. Especially when starting with such a niche. You will find that astro equipment depreciates even faster than cameras. Almost all of astro stuff I got, I bought used for 50-60% of the retail price. So when I decide to get rid of it, I might loose maybe 20% of my initial "investment". If you buy new, that's 50% of that price you throw away right of the gate. Engage your local astronomy community, that's usually the best place to buy used gear, instead of eBay or some such.

Good luck with your pursuit.

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