iantaylor2uk

Any takers for this? https://www.space.com/vaonis-hyperia-telescope To be honest I would think a 10micron mount and a 120 Tak would be much better (and considerably cheaper)

I have used some large heavy reflectors in the past (such as a 12" f/4 Orion Optics Newtonian) and the benefit of their aperture is often outweighed by their weight and size. I have recently started using a much smaller William Optics 81GT IV refractor, mainly for astrophotography, and as well as the optics being excellent, you also have a shorter focal length so you get a wider field view. In my case I have a separate mount (a Losmandy G11) so it easy to swap from one telescope to another. In terms of optics, it is not downgrading, but it is certainly a lot smaller and lighter scope. Incidentally, I tend to use a 1x flattener with this scope, so the focal length is around 475 mm, whereas a lot of people with this scope use a dedicated 0.8x flattener so would have an even shorter focal length. I can certainly recommend this as a great refractor.

Nice image - as it happens I also took an image of this the other night also with 3 min subs using a ZWO 071MC Pro camera on a William Optics 81 GT IV, and I used an Optolong L-enhance filter. Only managed 30 images though (about 1.5 hours in total). This was stacked in DSS and further processed in Nebulosity 4.

If you put items on eBay for auction, and the item is selling is in short supply, you will end up with plenty of interested buyers and the item will find its own price (this is what is known as supply and demand). I'm not sure why people on here think you should sell things cheaper than what you bought them for if there are lots of people interested in buying an item.

Great image - I remember having a few Atik cameras over the years - an Atik mono HR and a couple of Atik 16ic cameras (one colour, one mono) - I think the only issue with those cameras was the size of the sensor (compared to today's CMOS cameras) + I tried using the mono Atik 16ic camera as a guide camera, and since it was only USB1 it took ages to calibrate with PHD2. However, they did produce good images though.

You have an f/2 system, you do not need 4 mins!

I use a WO 81 GT IV with a 1x Hotech SCA flattener and the ASI Air Pro tells me the focal length is 475 mm and I've had some great images from it. I guess if you went for a 91 with a reducer it would be a similar focal length so the only advantage would be the slight increase in aperture.

To be honest, with that set-up, I would go for 30 second subs (even with the L-enhance filter on) and bin 1x1 (you can always bin 2x2 in software later if you want).

I only usually take 10 flats/10 darks/10 dark flats for calibration but I often see people on here take 50 or more flats. Is there any benefit to taking more flats, and is there an optimum number?

I stand corrected, but I can’t see any circumstances under which you would want to stretch a dark frame.

I have a ZWO 071MC Pro camera and have never seen amp glow on it. I've been very pleased with the camera. I also have a ZWO 120 mini MM guide camera. If you go the ZWO camera route you can also use an ASI Air Pro which makes life much easier in many ways.

Not sure what flattener you have used. I have got good results with the Hotech SCA 1x flattener on an 80mm f5.9 scope. Sensor needs to be 55mm from shoulder of flattener but doesn't seem too sensitive.

Thanks Jeremy

Yes still have a bit to learn on processing 😃

I managed to get 2 hours of data on M33 last night. I used my ZWO 071MC Pro camera (gain=150, exposure 60 secs, sensor cooled to 0 C) on a William Optics 81GT IV (with 1x flattener) on a G11 mount, autouided using an ASI Air Pro. Stacking was in DSS and further processing in Nebulosity. (Flats, dark flats and dark frames all included in DSS)

I needed another 7lb counterweight for my G11 and couldn’t find anywhere in Europe that had them in stock. In the end I had to order direct from Losmandy and it only took 2 weeks to arrive, so great service. The counterweight only cost $50 but the postage was $80. Incidentally I had an old counterweight in the shed from a previous mount and asked a local engineering workshop how much it would cost to enlarge the hole so it could fit on my G11 and was quoted £300!!!

I have ordered one of these and plan to use it on my Losmandy G11. There is a G11 up for sale on astro buy and sell for a reasonable price (although it is Gemini 1 rather than Gemini 2). That mount would easily cope with it.

You would have to crop the image to get rid of the funny shape stars at the edges if you don't use a flattener, if you use an APS-C sized sensor. I use the Hotech SCA flattener on my WO 81GT IV and it works well with my ZWO 071MC Pro camera.

Great review. I have an Altair Astro Starwave ED 110ED-R which got a good review in Sky at Night magazine (https://www.skyatnightmagazine.com/reviews/telescopes/altair-starwave-110ed-r-refractor/) and I have got some good images with it (once I used a flattener and a UV-IR filter, as my ZWO camera doesn't have one). Build quality is good, and I imagine it would be very similar to your 102 ED. The only thing is that in mine the glass is FPL-51, not FPL-53.

Good review. I also recently got the ASI Air Pro and find it fantastic. I usually get the main and guide cameras focussed separately, and polar align with Polemaster, before switching the AAP on. Not sure what you mean when you say Polaris is way off when you polar align. Polaris is about 3/4 degree from the pole so should be away from the pole axis when you are correctly polar aligned. I also tend to use autorun rather than the live or plan options.

Thanks Richard - the recent image I took can be seen at: https://drive.google.com/file/d/1zt3eszt9nfapXpEzjNONWBP_0K4MSNSQ/view?usp=sharing After stacking in DSS, I did some basic processing in Nebulosity, but may look into getting Pixinsight

Great camera - I love mine - only issue is because it is such a wide field of view you need a good flattener (for refractors) or good coma corrector (for reflectors) or else you have to crop the final image.

Great image - I took a look at NGC 7000 the other night, with a slightly longer focal length telescope (478 mm) and used a L-enhance filter, but only got 2 hours worth of data. The 10+ hours of data but the care you have taken in processing the data make it a great image.

Thanks Jeremy

Managed 2 hours on NGC 7000 last night. Used a WO 81 GT IV telescope with 1x flattener on Losmandy G11 mount. Camera was a ZWO 071MC Pro (gain 90, 120 sec exposures, sensor cooled to 0C). Autoguiding using ASI Air Pro. Also used an Optolong L-enhance filter.