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This is one of the threads on CN which has several contributors some of whom appear to be very well experienced visual observers. They have used several higher end refractors visually as well. It was from this thread and others that I gleaned the visual performance of the 120/140 Askars was good. Have I been reading this thread through a pair of rose tinted glasses? Thanks. https://www.cloudynights.com/topic/900932-askar-140-apo/

I have thought about putting a hand warmer in my eyepiece case! I think the small size of eyepiece lenses is also relevant. Even the largest ones will be quite rigid compared a big floppy newt mirror for example.

Here is one of my old posts from 2010 where my wife and I visually compared a 5” refractor to a Skywatcher 8” F/6 Newtonian… “I was really enthusing about how good the seeing was so Mrs Dweller25 decided to come out and have a look. Now this is a rare event as Mrs D and the cold night air don't mix so to spice things up a little I suggested a shootout between the 5" Takahashi FS128 and the Skywatcher 8" F/6 Newtonian. Each of us would take a turn observing and drawing Mars in each scope so we could compare and contrast. Seeing was very good - AII, temp was -4'C. We concluded :- 1. Mrs D25 has better eyesight than me - I have astigmatism 😕 2. The humble Skywatcher slightly outperforms the Tak 😱 🙂

I saw this in the challenge section but can't comment there of course. I like this version very much as the other ones taken during full darkness don't do you justice. It's a shame the dark sky park doesn't reach as far as the coast ! The star spikes look good and well controlled. The fact you've got nice reflections also draws me in Dave.

Imaging near the Zenith produces massive image rotation. Even if the Seestar can compensate when stacking, the useable field of view reduces from a tall rectangle towards a square. The image below has been black level adjusted to demonstrate - M51 was about 82 degrees altitude.

Curves will give you more control on width of peak, or use selective colour.

It’s advertised as 1.52KG for the OTA out of the box - that must include the built-in mounting ring and dovetail. Sorry I don’t have any scales at the moment.

Thanks Mr Spock, Pulling out one particular comment, I was interested in the variable polariser. How does it affect the appearance of jupiter, wrt bands, GRS, etc?

Thinking about a newt. A mirror at uniform temperature, whether 0C or 40C, has the same shape, and therefore consistent performance. A decent mirror has very low thermal expansion, which means cold edges and hot middle should have a small effect on shape. How much this matters depends on the temperature difference. It is all a matter of degrees. OK I'll get my coat. An eyepiece (even a jam jar size multi element) is small and low mass compared to a 10" or 12" mirror. Temperature difference from centre to edge is going to be small. So performance hit should be small. Cooling is going to be fairly quick. So by the time you have thought much about whether view it good, temperature has become stable. In 2011 I trialled a solution to the 'foggy eyepiece' and 'not enough pockets' problem. A fibreglass box (strong enough to stand on) containing large resistors and a fan on the aluminium plate. Power from a 12V supply. Just keep eyepieces in there when not in the scope I posted about it on SGL and there was zero interest!

Yep - the lower setting of the 3-8 is closer to 3.5mm I reckon.

Great picture! 🙂 Exactly one year ago it happened that I captured the Markarian's Chain. When I run a StarXterminator on it I found 63 galaxies. How many of them you have in your picture? 🤔🙂 https://www.astrobin.com/v6wchq/

Following on from this, I’ve done an analysis of my mount’s performance using sets of raw frames that I took a few weeks ago. As it is SharpCap specific, but may be useful to others, the write up is on that forum. https://forums.sharpcap.co.uk/viewtopic.php?t=7630 Geoff

I found that there is a mechanical stop at about 85 degrees in elevation (altitude), so there will be a "blind" cone within about 5 degrees of the zenith. The "voice" confirms the end stop when you hit it. If clouds permit, you can wait until the target drops in altitude. Geoff

Thanks Dirk. Interesting comments!

Thanks Alan, Thanks to many people in the forum, plus other research, I decided early on that the az-eq6 was to be the foundation stone, and building from that. So, a 200pds and 120ed will be OK. But, it could handle bigger. Problem is, my ability to handle the larger scopes is inversely proportional to my age now. But, I may decide, 8" is all I need. 😊

Indeed the beauty of the Az-eq6, is it can hand both simultaneously, so I could build up a record of differences. Obviously there will be times when I only want to have one set up, but the options there.

Probably not with a mak.

Thank you Paul. I ran the same in PixInsight using the TypeCat script and pulled out a lot of quasars. Currently, calculating the distances on a few to see if I’ve beaten my most distant object captured.

I keep mine in a tray with the eye dust cap on to prevent misting. I don't have enough pockets for all of them anyway, especially the larger ones

Those histograms do not look like the histograms of linear data. White balancing cannot be performed on non-linear data. It raises the question about what kind of workflow you are following. For instance, are you raw-converting your images before stacking or do you put your raw files directly into DSS?

I haven't started my review yet. I still have to give it a full workout on the 4" Tak. On the 12" I was able to use it at the 5mm, 4mm and 3mm settings on the moon a couple of nights ago. Field curvature wasn't as evident as longer focal lengths and not intrusive. The eyepiece was sharp at all settings against the 4mm Nirvana, 7mm, 6mm and 4mm Circle-T orthos, 6mm SLV, 3.5mm and 5mm LVWs, with some variation - it wasn't a match for the 8mm LVW and the orthos looked 'cleaner'. It couldn't match the 4mm and 3.3mm TOEs in any area; the TOEs were sharper, clearer and had better contrast; they were able to pick up the tiniest of craters - I won't be selling them! I did note the magnification looked the same as the 3.3mm TOE at the 3mm setting - objective rather than scientific. I also had to fold down the eyecup to feel comfortable. My tiny 4mm ortho was easier to look though!

I moved the exposure time right down to 1ms. Earl - When you "You might need to add an extension tube to achieve focus." - what do you mean? Can you show me a link please?

It’s my understanding that the figure of a Newtonian mirror can significantly change shape whilst cooling, with the edges cooling faster than, and thus at a lower temperature than, the core, inducing turned-edge-type aberration. I’ve often seen it in my own 12”, starting off a session with seriously different in-and out-focus patterns, gradually becoming hardly-different later on. This describes it: http://www.loptics.com/articles/fourlessons/fourlessons.html

Our moon is a wonderful body and one can never tire of observing it, whether with naked eye, or with binoculars or telescope. Under the right seeing conditions, and a good instrument, some breathtaking scenes can be enjoyed. Many superb images of our neighbour have been created by SGL lunar imagers, and rival some taken by larger Observatories throughout the World. Of course the Moons gravity has an influence over the earths Ocean Tides too. Solar Eclpses too are a joy to see.| It seems also that humans are getting closer to visit the moon and stay for periods of time to do deeper studies of it's make up. Finding water there is an essential task. Ron.