michael.h.f.wilkinson

Nice one! Merry Xmas!

Going for second-hand is always a good idea. Generally, astronomers take good care of their kit, and something as simple as a Dobsonian doesn't really wear out readily.

+1 for the classic Dobsonian. That gives you the best bang per buck aperture-wise, and aperture is king when observing

I managed to get a very good offer on a second-hand pair of Nikon Monarch 7 10x42s, and they are excellent. For astronomy, I prefer something bigger, and currently use the Helios LightQuest 16x80. I can use these hand held, but know that many struggle with that. I also have a monopod with pistol-grip ball head, which is very steady indeed. On a Dutch site there is an offer for Omegon-branded 15x70 BA-8 binoculars for just 175 euro (same as the excellent Helios Apollo 15x70). That is a steal if they are in good nick.

Not too surprised. Many red giants are semi-regular long period variable stars. Not likely to be the the herald of anything spectacular

According to The Register, mirrorless cameras should be called EVIL (Electronic Viewfinder Interchangeable Lens) 😜

As I understand it the optimal magnification is given by the aperture of the scope in mm, and doubling it does not necessarily reveal more detail, but might make detail easier to spot, and doesn't clearly show fuzzy edges. Much depends on visual acuity, however, and the contrast on the object in question. The moon and Mars take quite a bit more magnification than Saturn or Jupiter.

That is apparently a clone of the TMB Paragon I used to have. I foolishly sold it, regretted it and got the Vixen LVW 42. That is also comfortable, and certainly very sharp, but it has quite a bit of distortion, and is a bit more prone to kidney-beaning and blackouts than the Paragon.

I will wait and see the reports of others, before ordering the XW 40, as the LVW 42 get very limited use (the Nagler 31T5 usually gives the better views, with a darker background). Buying the XW 40 would get in the way of more "urgent" upgrades (like the 6" solar scope project). Choices, choices.

Agreed. The XWs in my mind perform like 70 deg FOV 20mm eye-relief orthos. The fact that my eye can relax as I view the image means I can tease out more detail than when I need to strain my eyes by glueing my eyeballs to the eyepiece. Note that the number of elements was never the most deciding factor for light scatter and internal reflections, it was the number of groups. Scatter at glass-glass interfaces is far lower than that at glass-air interfaces. There is also an upside to more glass-air interfaces, i.e., more degrees of freedom in the design of the optical surfaces, so better correction of other aberrations over a wider FOV.

I see FLO has them listed already: https://www.firstlightoptics.com/pentax/pentax-xw-40-r-2-eyepiece.html

I am seriously interested in the 40 mm, might well replace the Vixen LVW 42 mm I have three shorter XWs (5, 7, and 10 mm) and love them to bits. I quite like the Vixen LVW 42, but it nver was quite as comfy as the TMB Paragon 40mm I foolishly sold.

Pretty decent for suburban skies. I do get much better views when I am out of town, but for a quick session I cannot really complain

I typically used the ASI224MC with a regular Baader IR/UV block filter, but have also used the ASI224MC with an IR long-pass filter using it as a mono camera. works nicely.

+1 for the flip mirror, it takes a lot of the fuss out of getting the camera on the chip. You will need a lot of back focus for it to work, however. It is not always available on a Newtonian design

The software needs to be installed on the laptop or tablet you are using. Think of a planetary camera like the ASI224MC as a web-cam on steroids: yes there is firmware on board, but this rarely if ever needs updating, the main issue is installing drivers and capture software on your laptop or tablet.

It is not just the silver on the mirror, it is all the equipment you need to actually silver a mirror, the money required to buy and maintain the cnc machine, etc. The actual cost of the sand from which the silicon used in your CPU is made is nothing whatsoever, but I can see why the CPU itself costs quit a bit more. Being in the hobby for 40 years, I have seen the prices of telescopes fall (even when not taking inflation into account), and the quality and diversity of optical equipment go through the roof at the same time. I own not one but several Fabry-Perot interferometers for H-alpha solar imaging which would have cost a fortune when I started out. The same holds for my Ca-K kit. The choice, performance and quality of eyepieces has skyrocketed since I started (when a quality Plossl or Ortho was about the best you could get here). Quality optics have never been more affordable. This is not to say certain companies mightn't be playing nasty trick on us, but we should not tar the entire industry with the same brush

I used to have the ASI224MC, and really liked it. It is powered through the USB cable that attaches it to the laptop or tablet. Below are two Jupiter captures with my C8 (on an EQ mount)

I returned from a salsa party just before midnight to find the skies beautifully clear. I didn't have time to get the scope out, so I grabbed the Helios LightQuest 16x80 bins for a quick look at the sky. Orion's sword was tempting as ever, so had a quick look at M42 and M43, nicely resolved in these big bins. Next I had a quick look at M45, which is always gorgeous in bins. I pointed the bins towards M33, which can be a tricky target in suburban skies, but I got it bang in the centre of the FOV, showing up surprisingly well. I also visited Andromeda to check out M31, M32 and M110, before moving to first the Double Cluster, and then M34 in Perseus. Just to stay in the same part of the Messier catalogue, I snapped up M35 in Gemini, and M36, M37, and M38 in Auriga, all beautifully resolved in these bins. M44 proved a bit more elusive, being placed in a brighter area of the sky, over the city centre, but I got it in the end. I ended up with M81 and M82 in Ursa Major, after a brief but futile attempt at M101 and M51 (both too low to make out). M81 and M82 showed up nicely, however. I was glad I could spend some time under the stars again. Binoculars are just superb for these brief opportunities.

I tend to store my scopes in a only slightly heated garage (just enough to keep the frost out), and that means temperature differences with the outside world are not that severe. Having said that, I do not believe going from say 20 Celsius to -20 Celsius or lower would cause thermal shock, as the heat capacity of air is so low, and free convection is pretty inefficient when the objective is well recessed within a dew shield.

I have no experience with the Altair offerings, but am very content with all the ZWO cameras I have had to date (ASI130MM, ASI120MC, ASI224MC, ASI174MM, ASI178MM, and ASI183MC (I still own the latter three)) and likewise for their electronic filter wheels (both the full size and the mini EFW)

The 183 has smaller pixels, leading to a smaller dynamic range at full well depth. So in principle, the 1600MM will not saturate as soon as the 183MM, assuming the same quantum efficiency (I gather the 183MM has a peak quantum efficiency of 83%, so it is hard to beat). Stacking a sufficient number of images should however allow you to compensate for the lower dynamic range of 183MM. I have the ASI183MC, and my first attempt at deep sky wasn't too bad. Just one hour of data in 60s unguided shots with my 80mm F/6 triplet and 0.6x reducer.

I have never had a 32 mm TV Plossl, but do have the 25mm, which is fine in terms of eye relief (about 20mm, ideal for me with my glasses). However, I did have issues with the otherwise excellent 36mm Vixen Plossl. Eye relief was way too long for comfortable viewing. I did sort of get used to it, but once I got the TMB Paragon 40mm, with its extreme viewing comfort, and 20 mm eye relief, the 36mm was sold. Because Plossls are scaled designs (a 32 mm is simply a bigger version of the 25, and therefore has a longer eye relief to match), this effect is unavoidable. All you can do is recess the eye lens, or add a longer eye cup.

I haven't had any real issues with my APM 80mm F/6 triplet. I do not have a dew heater (should get one), but dew always first builds up on the outer surface, so imaging is curtailed when that happens (which is rare, given the deep lens hood). When I bring the kit inside, the front element does generally fog up, but I only store it in its case once all signs of dew have disappeared. I have had this scope for about 8 years without any issues.

Brilliant set, and well deserved winners