michael.h.f.wilkinson

Fantastic image. I am really tempted to get such a photon hoover. At a similar focal length my scope is F/4.8, so 5.76x less light hitting the sensor, requiring 21.3 hours to get the same amount of light. Ouch!

Hi Dave, welcome to SGL. The combination of an EQ3-2 and 6" Newtonian should work on planets and moon with a suitable Barlow and planetary camera, but for deep sky it is going to be hard. I do image on an EQ3-2, but with a much shorter focal length, either a DSLR with telephoto, or a short APO refractor. For my 6" F/5 scope I always use a much heavier mount. If you have something like a 200 mm telephoto, you can achieve results like these on your mount The latter was with a modded EOS 550D, without guiding, just stacking loads of short exposures

I considered this one as well, but the eye relief is too tight for those who need to wear glasses. If you don't need glasses this should be a top notch EP

On my Vixen GP, and GP-DX mounts, the 6 "Schmidt Newton works well, but I wouldn't want to go beyond that. It is not just the weight, but also the tube length and associated torque that will pose big problems.

In my Coronado SolarMax-II 60 mm, and before that in the Lunt LS35THa) I use a William Optics 7.5-22.5 mm Zoom II EP. It is no longer made, but you can get clones, like this one from Omegon: https://www.omegon.eu/eyepieces/omegon-premium-7-5mm-22-5mm-zoom-eyepiece/p,33244 The Lunt 7.2-21.5 is also good, but has an eye relief that is just too short for me with my glasses. A wide angle EP is a bit useless, as the 4 mm blocking filter basically restricts your practical FOV. This is why the narrow FOV of the zooms at their longer end is not a problem in this case. Chromatic aberration is also not a problem.

I find an aperture of 50 mm is very small for an instrument costing that much. That will severely limit the performance

It is a very useful filter, and yield very dark backgrounds, even from my suburban garden. The only issue is the odd star colours (and some difficulty focusing on stars due to the low light levels). Any reflection component in a nebula is gone, as well

I will give the colours a tweak tomorrow. Now stacking M78 data.

Managed to grab another 5 hours of data on the Rosette, and added these to the 7h 21 m previous data. Improvements are subtle, but certainly the S/N gradually improves. Didn't do any noise reduction, and I might want to crop the results a bit , or get some more data, should the skies clear again. Star colours are off, due to the use of an Optolong L-eXtreme filter, so I might want to add some data without

Just thrown in the towel. Hazy cloud is coming in, and the main targets were sinking low. The Leo Triplet is enticing, but with that haze, I will give it a pads. Captured a good 7 hours worth of data, one batch is stacking now. The rest will be processed tomorrow

It is heading for -15 °C here

Better make the most of it, so two scopes and cameras clicking away The Meade SN6 gunning for M78 The APM 80 mm capturing more data on the Rosette

Got a total of 5 hours of data on the Rosette last night, using the usual combination of APM 80 mm F/6 with Tele-Vue TRF2008 0.8x reducer, with Optolong L-eXtreme filter, and modded Canon EOS 550D on the little EQ3-2 mount. I stacked them in APP, and added them to the 2 h 21 min of data captured on January 30 and February 9. I cropped the results and did some tweaks to the colour. I hope to get another 5 hours tonight, as I feel that could really bring out the fainter outer regions

Got 2 h 45 min of data with my Meade SN6 6" F/5 Schmidt-Newton and ASI 183MC camera last night. Wasn't that sure I would get much from a Bortle 4-5 location with quite a bit of haze in the air. Stacked the data overnight in APP and was quite pleased with this first attempt. I did a quick tweak of colours and cropped the image in Gimp to get this. Needs more data, of course, and I hope to add at least as much tonight

Lovely image!

Got two scopes imaging tonight: the APM 80 mm F/6 triplet with Canon EOS 550D aimed at the Rosette Nebula again, and the Meade SN6 6" F/5 Schmidt-Newton and ASI183MC aimed at M78. Fingers crossed both set-ups behave

Two of my PhD students got papers on image analysis of astronomical data accepted and published this month. The first one is a paper on how to detect faint sources optimally, in which we show a program developed at our university works better than the other tools tested, including the stalwart Sextractor. It was published in Astronomy & Astrophysics. The other is about a new way to analyse (future) SKA data on the Epoch of Re-ionisation, when the first stars started to ionise the neutral hydrogen, causing local dark bubbles in the 21 cm emission (now redshifted to much longer wavelengths). The aim is to determine the distribution of bubble shapes and sizes to determine the nature of the early ionising sources. It was published in the Monthly Notices of the Royal Astronomical Society. Both are open access papers, so if you're interested, feel free to download them.

It looks like a blue-green and slightly fuzzy version of Saturn. I first saw it through a 20" Dobson at Olly Penrice's place, and was amazed at how intense the colour was. Low in the sky during summer, but very much worth looking for

Aperture is king in planetary imaging, so I cannot see the 115 mm doing better than the 130 PDS, despite the shorter focal length of the latter. What I would do is get a good Barlow or tele-centric lens to extend the focus of the 130 PDS. As an alternative, you can also use eyepiece projection. Much also depends on the camera in use, and in particular pixel size.

Here is the result of the area around Alnitak, combining a whole lot of sessions, with, or without Optolong L-eXtreme Some edges do show up, especially between overlapping stacks taken with different filters, so of course you crop the result Still needs more data (even with 7 h 37 min of data). Note I did not do any denoising on these data

I used DSS for a while, then trialled APP, and promptly bought it. Well worth it in my experience, I find it much more intiutive, and it gives me much better results

I personally stack each session, and then stack the resulting stacks, and by using weight maps produced during the stacking of each session odd edges are minimised if you have slightly different orientations. Astro Pixel Processor also allows you to do multi-session stacking, in which case you have to indicate which flats, darks etc to use on which lights. The advantage of doing it my way is I do not necessarily have to keep all subs on my hard disk, just the resulting stacks and corresponding weight maps. Stacking the results from different sessions is very quick too.

I much prefer a 2" star diagonal to a 1.25" even when using 1.25" EPs, as the 2" have a much larger completely flat surface. More importantly, it allows use of 2" EPs which can give magnificent wide field views. I have an APM 80 mm F/6 triplet, which gives a massive 5.3 deg field of view with the 31 mm Nagler, and 3.75 deg with the 22 mm Nagler . The view of M33 in the latter from a dark site in France was one of the best views of that object I have ever seen. I have a fairly cheap SkyWatcher dielectric one, but also a Denkmeier Filter Switch diagonal, which looks like William Optics build them. This one I use most, as I can slide 2" filters in and out of the optical path quickly. The Denkmeier is supposed to be the better one, but you will be hard pressed to see the difference.

I have a very nice little APM 80mm F/6 triplet, and tried a Morpheus 14 mm in it, and it worked well. I also have an ST80 for guide scope duties, and the difference in image quality between the two scopes is very significant indeed

It certainly helps to get the images approximately aligned, but a slight rotation or shift isn't the end of the world. This is the result from 2 sessions, and I had some 14° rotation between them. Did not cause big problems.