Datalord

2 hours ago, ONIKKINEN said:

There are also the IMX461 based medium format cameras, or the GSENSE4040 based ones, both around 50mm+ diagonal. Still costs about as much as a decent car, but nothing compared to the 700mm RC so almost a good deal at 10k£ (at least).

Yeah, I looked at qhy for their cameras. Honestly, the 411 based cmos at 150mp looks like an amazing camera. Binned 2x2 it gives a full well of 320k and a huge sensor. Btw, the 0.7m scopes come in at $200k+, so the cameras are a drop in the ocean to compare. 

2 hours ago, DaveS said:

This is the FoV with the Gsense 4040 on the 0.7M RC, again using Copeland's Septet as a reference

This actually looks very good. 🤔

2 hours ago, DaveS said:

And just to show that you don't need a big RC to get a narrow FoV, just need to be totally barking. My ODK 12 with my SX Trius 694

And yes, that would indeed be barking mad. Seems like you would just waste a whole lot of telescope. 

Adding fuel to the fire, what cameras are even available for such a monster? I saw the qhy6060 with an 80mm 10*10 sensor mentioned in the thread, but any other available? 

Hmm, I'm actually surprised. I also have my 12" 2.4m RC, but I thought having a much larger scope like that would make more of a difference. Obviously acquisition time "should" be faster, with all the caveats of camera etc, but I really thought a tripple in FL would be bigger. 

On the flipside, that means a lot of the usual targets are still viable. 

1 hour ago, DaveS said:

Here we go, Copeland's Septet in your 0.7M dia, 8.4M fl 'scope

Damn, still looks small. I don't know that one, what's the size of it? 

Yeah, everyone going for galaxies makes a ton of sense. I have a love for the ARP catalogue, so lots to spend time on there. 🤔

I'm curious what could be good targets for these huge systems if they are used for pretty pictures? 

Impressive image! What camera did you use?

Fantastic image. Very well done.

Agreed. It's incredible. Over two years since I had my hands on my setup in Spain and it still just runs perfectly. 

I've had the scope for a while now, but getting the camera delivered has been a right pita due to a hopeless company I shan't name. Yesterday I finally got it running on a beautiful day and messed about processing it. 

This is from yesterday, Lunt 152THa with a ZWO ASI 174. Roughly 1000 frames, stacked in Autostakkert and processed in PixInsight and Photoshop.

51 minutes ago, Highburymark said:

Personally, I’d look at Solar Spectrum first instead of Daystar - distributed in Europe by Baader. Have a look at the Astrograph website here in the UK - they sell Solar Spectrum. Also have a look at Solarchat (‘commercial filters etc’ forum) - there are some recent reports on there that provide views on quality and reliability of this type of filter. 
 

Had a look. Everything is out of stock, so that would have some long wait. And the faff would remain.

I think I'll go the Lunt road. It seems like the easiest way for me to achieve what I want. If it goes pearshaped I can also easier sell it I think.

Thanks everyone!

I looked more at the DayStar Quantum. Have to say that looks appealing if I can use it with a large refractor I plan to order. 10 min heating time seems like a very small price to pay compared to the 1-2 hours I usually have to cool my nighttime scope.

If I went that route for an f/7 refractor, I would need:

1. DayStar Quantum SE 0.3A

2. Baader E-DRF rejection filter in the right size.

3. Rejection filter holder.

4. Barlow x4 or aperture reducer+barlow

Is that correctly understood? While appealing, experience tells me this will be a whole lot of faff...

The alternative is a Lunt LS152. Made for purpose and would cost the same as the above.

2 hours ago, Highburymark said:

The advantage to modding an existing frac is you can use two larger external etalons, which normally offer more uniform contrast across the fov, compared to smaller internal etalons, which most solar scopes are built around (producing a ‘sweet spot’ rather than more even disc detail). Catch number 1 is they are more expensive. Quite a lot of Lunt scopes combine a small internal etalon with a larger external one - these can be excellent.
Then obviously, more aperture reveals more detail, and allows you to retain sharpness at higher powers. For the money you’re investing, you should be looking at 70mm-100mm double stack, or LS130 single stack. The new Lunt range is modular, so you also get an ED night scope as part of the package.
Catch number 2 is that all etalons are unique and variable, so there will always be exceptions to any rule - both nice exceptions and not so nice ones. I’ve seen 60mm single stack scopes that knock your block off with fine detail, and double stacked scopes of 90/100mm that have left their owners disappointed. But 99% of the time double stacking transforms surface detail and comes highly recommended.
The third option is a rear mounted etalon (Daystar, Solar Spectrum), which can be used with any parent refractor, but these come with high power barlows to work at around F/30, so are mostly used for close up views, and require v good seeing to strut their stuff. They also require heating for 10 minutes before they’re on band, so can’t really be described as ‘grab and go’.
I say this all the time but it bears repeating, all manufacturers of commercial solar etalons produce poor examples. Some more than others. So do your research - Solarchat and Cloudy Nights are particularly useful forums. If you are not able to test the product out first, make sure you buy from a reputable dealer who will take back substandard filters. Hopefully then you’ll end up with a scope that will provide you with decades of enjoyment. There’s nothing in the night sky that in my view compares with the sun in hydrogen alpha - watching our own star changing every day never loses its appeal.

Thanks, that's a lot to consider.

Being completely blind to the pitfalls, I am close to deciding on a second scope for home use, which would be a 140mm or 160mm refractor. Is it possible to get these external etalons in that size?

Yes, it's not for lack of choice. That's almost the problem. What I don't want to do is buy something I want to upgrade in 3 months time, so might as well go for proper gear. 

Interesting about coronado, I thought they were a premium brand. 

I'd prefer to get something purpose built instead of modding a different frac. Maybe I'm wrong? 

I captured this data in December and life sort of kept me from doing something about it until recently. 

13 hours of narrowband in 600s bin2 on my RC12.

Ok, here it is without humanoids.

I've been pondering the virtues of solar observation for quite a while and I think I want to try it out. However, I don't want to do it half-assed, so I need some advice on what great gear combinations I should look at. I don't really have a budget, but I'd probably keep it below £10k.

I will put it on my 10Micron GM2000 mount, so that's not a problem.

Is there anything other than scope and camera I should consider?

18 minutes ago, wimvb said:

Maybe we should call this the santa nebula.

Great image, btw

Thank you!

Here's Santa for you, on the 24th. A bit scary, very 2020.

This one took me months to finish due to a stressful time with lots of work and a move from UK to EU. Finally got some calm to sit down and process this data.

I wanted to see what I could get if I trained the big RC on the core of M33 and due to a few factors it kinda just continued. This is the best data from a total of 30+ hours captured.

One of my goals with this one was to see how much detail I could get with the Ha added to the mix. Having a peek into the star nurseries of another galaxy is super intriguing to me. I'm not sure I like the aesthetics of this image, but just looking at the details is fascinating.

For example this one in the bottom left:

I can't help but wonder what led to such a big ring shaped hydrogen cloud. And the stars in the center must be incredibly bright.

I'm going to be the dissenting voice here. A DSLR is indeed a great camera, I used a 6D myself, but don't underestimate the power of cooling. It is a whole different level of clear image you get from a - 40C sensor compared to a 30C heated by a 600 seconds shot. 

20 hours ago, tomato said:

Had another go, toned down the stretch a little

Infinitely better. Very nice.

1 hour ago, tomato said:

Are the inky black regions in the top right genuinely that dense or is that my processing?

I think you went a bit overboard in stretching and contrast on this one. You've also lost some of the colour you had in the first image. 

1 hour ago, tomato said:

My plan is to try and get a 24 hr total , 12 panel M31 LRGB mosaic, and see how this compares with this quick and easy result...

24h data vs 1½h? How will you ever compare those results?

It looks to me like you have some problems with focus. How did you focus for the various filters?

22 minutes ago, mftoet said:

When I acquired the Epsilon-180ED, the RASA systems weren't released by Celestron. In the late analogue / early digital age, a friend of mine used an Epsilon-160. I fell in love with the crisp stars that telescope produced and promised myself I would acquire one some day. About 10 years later I ordered an Epsilon-180ED including the ridiculous expensive tube rings, base plate en 7x50 finder scope (which in the end I only use for star alignment after switching on the mount). Another thing that I like about the Epsilons (and other fast Newtonians for that matter), are the diffraction spikes. I know, you either like them or you don't. 

Would I consider acquiring a RASA instead of a fast Newtonian? Maybe, but probably not. A thing that would bother me is that the camera (and cables) must be placed in front of the corrector plate. I can imagine taking proper flats can be challenge with a RASA. So respect for those who manage to produce excellent images with these astrographs!   

  

I for one love the stars in the images from fast newts, including the 180ED. My RC does a reasonable job of it, but it does take more effort in processing to get stars under control and they never get the crispness of yours. And my RASA doesn't even come close.

Well done on that image.

11 minutes ago, gorann said:

Yes, I have the fast Ha and am waiting for the fast OIII but Baader seem to be still working on the next batch. 3 minute subs - this is a fast scope! What camera did you use?

It took them almost 1½ years to get a batch for me, so do whatever you can to get a hold of one! This is with the QHY247, so a CMOS color.

Not my usual time on a target, but some clouds messed up half the night, so 3 hours is what I had. It is one more to my collection of globular clusters with my RC.