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Everything posted by John
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I think we will be seeing a lot of stuff that was bought during the lockdown period up for sale over the coming months. Normally these folks would have to take a "hit" of around 30-35% of the value to sell on even if the gear is virtually unused. The current scarcity of new equipment and recent price rises will likely soften this "hit" though, until supplies start to come through again. The buyers here and on the UK Astro Buy & Sell site will generally be pretty savvy on price so with either avoid what they perceive as overpriced items or, at best, will make a lower offer. E.bay is a bit of a "law unto itself" price-wise and I see lots of stuff on there which is, IMHO unrealistically priced and some of the auctions seem to end at a figure which is surprisingly close to the normal retail price. The thing to do is to produce a comprehensive and accurate description of the kit and a good set of photos and offer it for sale at a price that seems reasonable to you. Don't use the "offers invited" ploy though, potential buyers tend to avoid that and it's not actually allowed on the classifieds section here.
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I've been doing a bit of research into the feature I mention above, Reiner Gamma and it is quite fascinating. It is the best example of what is known as a lunar swirl. I came across this nice little LRO movie about this feature: https://upload.wikimedia.org/wikipedia/commons/2/24/Reiner_Gamma_vid.webm Fairly readily visible in most scopes as well
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I've come in now with more cloud arriving. On the moon I finished my session with a look at the interesting pale feature Reiner Gamma which runs, or wriggles, past the crater Reiner. Very odd feature comprising of pale and darker material. Apparently it has no thickness to it and a strong magnetic field. Finished off with a pleasing split of Zeta Hercules which had risen out of the Bristol light glow into steadier sky. Nice session considering that it was raining from quite thick cloud 3 hours ago. I was using my 100mm F/9 refractor tonight but not an achromat I'm afraid. Reiner Gamma and Reiner Crater (not my image):
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I have a clear spell here now as well. Seeing not quite as good as a couple of nights ago but still nice. Interesting to see how features observed two days ago with shadow in them look now they are fully illuminated. Aristarchus is blazing white tonight. The steaks of impact melt material can still be seen running up the inner walls of the crater though. Sirsalis Rille looks nice too at the edge of the Oceanus Procellarum.
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Wide awake now - It's cleared earlier than predicted ! And my report is ....... it looks pretty much the same to my eye as it has for the past few nights Nice to see it again anyway.
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Moon through the Peashooter - 26th March 2021
John replied to Stu's topic in Imaging - Smartphone / Tablets
Nice Stu It's just cleared here so I'm off out for a look myself ! -
Unless I doze off !!!
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Solid cloud a light drizzle here so definitely no magnitude comparisons going on here tonight It's supposed to clear from around 1 am so I might get a chance then, if I feel like waiting up.
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Dew Shield for Stray Light Reduction
John replied to DanLXIX's topic in Discussions - Scopes / Whole setups
You can get thin foam foam sheets in hobby retailers that would probably have enough stiffness to make a suitable shield for a 150mm aperture. I needed to keep the top end weight down on my dob as well because of balance so I'm pleased that my half moon shield (which is an Astro Engineering one) weighs very little. -
Cloudy here tonight so I doubt I'll get a peek
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Good point. Must find a way to stop the uninformed having a vote
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Well they are cheaper than a Tak !
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Whats the furthest away thing you've imaged?
John replied to Astro Waves's topic in Imaging - Discussion
I observed 3C 273 a couple of nights back: https://stargazerslounge.com/topic/374487-from-near-to-very-far-quasar-3c-273/ I did also managed to observe the outburst of the blazar CTA-102 that @Owmuchonomy mentions here: https://stargazerslounge.com/topic/374482-whats-the-furthest-away-thing-youve-imaged/?do=findComment&comment=4061446 That latter one is the most distant object that I've observed. -
Quality eyepiece cleaning fluid v LensPen
John replied to azrabella's topic in Discussions - Eyepieces
I have used the Baader fluid and their micro fibre cloth to clean eyepieces for the past decade with no issues at all. I use a hurricane blower to puff anything loose from the lens surface before using the fluid and only apply it via the cloth as per Baader's instructions. The fluid is applied to the cloth as a fine spray in a small patch and then using the cloth gently onto the glass so there should be no excess to get between lenses etc. That is what has worked for me. I don't use the fluid very often. Most often all I need is a few puffs with the blower, with the lens held upside down to ensure that any debris falls away from the glass. -
Dew Shield for Stray Light Reduction
John replied to DanLXIX's topic in Discussions - Scopes / Whole setups
I use something similar on my 12 inch dobsonian. Its one of the half moon shaped ones to stop light getting onto the top of the secondary and inner end of the focuser. I've found it very effective. My light issues are from one general direction. For more all around problems a tube shape would be good. -
I'm no imager (really !) but I did actually manage to snap a bit of the Hadley Rille using my ancient mobile phone over the eyepiece with my 12 inch dob last year. It's not much to look at but I was quite pleased with it. I've got a better phone now so maybe I should have another go ?:
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That would be my suggestion as well
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Good night for Schröter’s Valley - 25th March 2021
John replied to Stu's topic in Celestial Events Heads Up
I felt that as well. -
Good night for Schröter’s Valley - 25th March 2021
John replied to Stu's topic in Celestial Events Heads Up
I've had some short cloud gaps so I've had some nice but rather brief views of the moon including the lovely valley @Stu has pictured. Rather solid cloud cover now though so I suspect that's it for tonight -
I'm getting short breaks in otherwise solid cloud here. A few minutes observing then a wait for the next gap. Better than nothing though.
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Good night for Schröter’s Valley - 25th March 2021
John replied to Stu's topic in Celestial Events Heads Up
Looking mixed here but I've popped a scope out in case I get a clear patch. Schroter's Valley is one of my favourites as well While doing that I watched a very bright ISS pass over, which was nice -
Schroter's Valley should look lovely tonight - if it stays clear
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Great report and photos Paul The views of the moon were very special last night.
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What focal ratio best suits a 40mm plossl?
John replied to bendiddley's topic in Discussions - Eyepieces
I have not used all the Omni plossls but I have used quite a lot of similar quality ones. Optically they perform similarly across the the range of focal lengths. In the shorter focal lengths (10mm and less) the eye relief starts to get pretty tight. In the central area of the field of view they will be fine in an F/5 scope but the optical correction may well suffer a bit in the outer parts of the field of view. There is not a sudden focal ratio cut off where an eyepiece simply won't perform, it is a gradual thing. By correction I mean distortions to star images, mostly caused by the optical issue astigmatism which causes stars to take on an elongated "seagull" shape towards the outer parts of the field of view. At F/5 coma can also be an issue in newtonians but that is usually generated by the primary mirror of the scope. This article gives more information: http://umich.edu/~lowbrows/reflections/2007/dscobel.27.html