chiltonstar

Well, I got up to 75x per inch last night with my classic (ie old) 4" f13 refractor and it was still pretty sharp. Saturn was glorious with a lot of detail, ditto Jupiter with I think a transit taking place, and even Mars at quite low altitude (23:30) was sharp enough to show the S polar cap well and a good bit of detail on the disk itself. A tribute to the seeing I think, odd really because the weather forecast was dismal with lightning flashes everywhere. Chris

Therapy, or buying another scope can cure this addiction.😼 Chris

Reminds me of the quote...."youth is wasted on the young" Chris

I think the issue of seeing the Encke division with a smaller scope can be looked at in a different way, as used in my "day job" as an atomic spectroscopist. Many features seen by eye or recorded with an imaging system are of course below the Dawes limit for the aperture, even Cassini. What we see is actually a convolution of the actual true appearance of the object with the instrument function (here Dawes, but in my area of work slit profile). A large, high resolution scope will broaden the feature a little but not degrade too much the intensity of the feature, but a small scope with low resolution will broaden the feature a lot and reduce its intensity a lot. In this latter case, the feature will only be seen with a scope delivering high contrast that can see the slight darkening produced by a convolution of eg Encke with an eg 1 arcsec Dawes function. My small Mak (127) has certainly shown Encke up on occasions when Saturn was high above the horizon, but the width of the feature as seen would have been very close to the 1 arcsec or so dictated by the Dawes limit for the scope (120mm). Chris

Indeed - isn't the fundamental point essentially (pin out of grenade) can paying lots of money for an expensive refractor really beat the laws of physics? Chris

I'd agree with Andrew S - clear when scrolling the page, or indeed if I move my head from side to side and look at it. Chris

Some interesting comments on seeing; I notice with mine (ZWO on 180 Mak) that where the poor seeing is of the sparkly, scintillating variety (you know what I mean) it appears to make no difference, but the slow swimming pool type that often appears if the sight line is over a hot road or roof or whatever, the ADC does appear to improve the view significantly. Chris

I was getting flashes from Marlow direction - a good way from Oxford. I had the live lightning map app running on my laptop outside to see how far away the lightning effect could be seen. Here, I thought the Perseids were a bit underwhelming, although there was 50% cloud. Chris

Wouldn't I need three for the tripod feet? After all, I'm 182 cm so it's not me that needs elevating.... Chris

My first attempt at Saturn this year; 1000/6000 frames with 180 Mak/ADC/AS120 colour camera. Image processed in Autostakkert/Registax. Oh for a bit of elevation! Chris

My pennyworth.....it's horses and courses really. My first scope, mainly for planetary and doubles, was a 102mm f13 (Vixen objective) achro refractor. It still gives excellent views of doubles, but it is only 102mm aperture which limits resolution and of course limiting magnitude - there are many doubles of interest with faint secondaries. It is also long and unwieldy. I then added a 127 Mak, which IMO is a truly excellent scope for the price, and enabled me to get to tighter doubles and fainter secondaries. To get lower, I then bought a 180 Mak which has enough aperture to reach many of the fainter doubles and (an important point) it is reasonably compact. Big newtonians and refractors may give excellent views, but they aren't that compact or convenient to use! For me personally, I have another issue as I live next to fields with wheat, barley and huge amounts of dust on occasions (eg yesterday) That makes open tube designs like newts or classical cassegrains less practical. Chris

I've just had a good session too. Jupiter was just visible through thin cloud, the shadow was clear but intermittent and then miraculously, the cloud cleared leaving a haze and the seeing improved. The shadow was sharp and stable and in the position indicated in SkySafari; Europa itself suddenly came into view as a lighter disk slightly higher on the belt than in SS I believe, and the GRS slightly earlier than the SS position. A glorious sight! Chris

Despite their current low altitude, I got a real treat last night with Saturn and Jupiter at their glorious best, despite the intense moonlight! Using my 180 Mak with ADC, Vixen SLV 15 mm, Baader Ortho 6 and 10mm and a 7.2 to 21.5mm zoom EPs, I had almost Hubble-like views for a few minutes as the seeing improved after a bank of cloud. Best magnification for J and S was about x245 and up to x300 once or twice. The GRS and surrounding area was clear and sharp and a beautiful pale rose colour, and the belts full of intricate detail. The colour contrast between Callisto and Ganymede was particularly striking as the two moons were close together (23:30). Nearby Saturn was textbook, with a very clear and sharp Cassini, banding on the disk, ring-on-planet and planet-on-ring shadows, a hint of the inner dark ring, and 4 or 5 moons readily visible. I tried taking the ADC off briefly (re recent post about the benefits or not) but there was little doubt that the visible detail was significantly better with the ADC, particularly on features such as the GRS. Chris

Yes, defo one for the 8 inch f8. It would be interesting to see how @John's baby makling performs on it, and maybe the classical cassegrain? Chris

Monday evening 3rd August at about 23:30, at an altitude of about 16 degrees (from Oxford). At the moment, the weather is uncertain so we may be lucky and have a clear patch or two. Chris

Small can be fun! I used my ED80 on my Vixen Porta2 to split it at x110; the easier pair split at x80, but it needed more for the more difficult unequal pair. I then moved the mount and scope into a nearby field to have my first look of the season at Mars as it rose. No detail, but always a thrill. Chris

Yes, with good seeing it is of course an easy pair of pairs to split with my 102mm f13 frac. Chris

But of course, you can't beat the limits set by aperture and resolving power. Chris

I can usually split them (180 Mak) at around x108. Worth noting that "split" is quite difficult to define, and what many of us see as split might not be to others. There is a formula which allows you to calculate minimum magnification: for a person with excellent acuity and with stars of equal magnitude, it is about 130/separation, or about 200/separation for many of us. Assuming somewhere between the two, Epsilon Lyrae would need about x72 magnification. Chris

I browse this occasionally - I'll have another look. Chris

As an alternative, I believe some suppliers stock extra tall pillar mounts. Chris

Many thanks, yes - it needs to be rigid like the original (ABS?) cap on the scope so I can drill it and mount a couple of brackets. Chris

For an objective prism system for spectroscopy, ditto some large gratings I have. Again, thanks to all for the answers. Chris

Many thanks, I'll try these two suggestions. Vinyl looks a bit soft perhaps, I really need something harder like ABS perhaps. Chris

Anyone know where I can get spare scope front caps from?? I particularly need one for an SW 127 Mak, od 150mm, id 144 mm in order to mount some optical kit. Many thanks, Chris