Louis D

Did you layer things on top of each other? How are you going to get to various bits and pieces that aren't in the top layer in the dark while observing?

Are the axes clutched on that AZ Pronto mount in some manner such that you don't have to turn the slow motion controls to move the scope from one target to another in the sky?

Before buying my first telescope 20 years ago, I asked for buying advice from the astro community. I was steered toward a very nice Dob that I use to this day. I had originally been interested in a Meade DS-10 on a pier mounted GEM from Walmart. It would have been horrible trying to deal with it's myriad issues. The fact that that particular telescope and mount have practically zero resale value 20 years later because no one would buy it except as parts speaks volumes.

That's a Jones-Bird design which is notoriously difficult to collimate and doesn't yield all that great of images even when properly collimated. The design uses a fast spherical mirror of 500mm focal length at a low focal ratio (remember, fast scope, losts of issues with a spherical mirror). It then places a "corrector" below the eyepiece holder to double the focal length to 1000mm. The corrector doesn't do a whole lot to fix the spherical mirror issues, though, so the images aren't all that great. I'd also be wary of any telescope including a 3.6mm eyepiece. It will be all but unusable in this scope because it will yield too high of a power for that scope.

That is a pretty snazzy box it comes in. Since it doesn't say it comes with a parabolic mirror, I'm going to assume it has a spherical mirror which won't produce as sharp of images as a parabolic mirror like the one in the Heritage 130p or the Skyliner 150p. Ironically, the latter is slower than the Skywatcher Explorer 130, and yet has a parabolic mirror. Longer focal ratios (longer, skinnier tubes) can often times get away with using a spherical mirror because the difference in figure between it and a parabolic mirror is so miniscule. Another issue with low end EQ mounts is that they oscillate horribly in wind, or if you touch the tube to focus or point it at another object in the sky. Dobs are rock solid under these conditions by comparison.

Well, how about the highly recommended Skywatcher Heritage-130p Flextube for £137? That would leave you with enough left over to buy a nice BST StarGuider 60º 8mm ED eyepiece (£49) for a nice higher power eyepiece that would be much better than the included 10mm eyepiece.

The clear glass filter is only need to reach infinity focus with regular camera lenses due to glass path distance issues. If this is to be a dedicated astrophotography camera, that isn't an issue because telescopes, unlike camera lenses, can be focused past infinity to compensate for the missing glass filter's focus requirements.

One thing to consider about the Vixen SLV is that the eyeguard does not retract to be flush with the top of the eyepiece. This costs the user 3mm to 4mm of usable eye relief. Personally, I think the 9mm Meade HD-60 is a fine eyepiece. In direct comparison to my 9mm Vixen LV, the Meade appeared to be better corrected in the center 50 degrees which surprised me quite a bit. Even at the edge it is nearly free of astigmatism or field curvature. It's also quite easy to take in the whole view with eyeglasses. Here's an optical test bench review of it by Ernest in Russia.

Don't get me started on the non-reciprocity in this UK-US relationship. There is no sales tax (VAT equivalent) on imports and no import duty on individuals importing less than $800/day/person into the US from anywhere. I've picked up several bargains from the UK with the favorable USD-GBP exchange rates of late.

I don't know about UK and European suppliers, but there are a copule of American custom wooden eyepiece case manufacturers. One is Wood Wonders and the other I know of is A Case for Astronomy.

I just wonder why anyone would use a Newtonian for astrophotography without a CC. Perhaps for planetary imaging dead center?

The Skywatcher CC has a 55mm backfocus requirement while the GSO CC is 70 to 75mm. This could account for part of it. The other part is probably that the GSO is a mild barlow at 1.1x while the Skywatcher is a mild focal reducer at 0.9x. Barlows add to back focus while focal reducers eat up back focus. Plus, there's the issue that the Skywatcher has what looks to be a nonremovable flange preventing insertion below the level of the focuser to intercept the focal plane earlier. The GSO CC is smooth, so it can be inserted below the focuser like a barlow to intercept the light cone earlier and project it back farther.

Neither does my Dob without the CC. I would imagine the 130p would reach focus with a GSO CC. Who would use the 130p-ds without a coma corrector when taking astrophotos? Thus my point, if you're using a CC anyway, it allows you to reach focus, so you might as well use the 130p.

I couldn't find the specs related to the secondary obstruction by diameter, so who knows what change was made there. I can reach focus with my limited backfocus Dob using a GSO coma corrector, so I doubt a dedicated, short tube is necessary for photography.

Dobs are awkward and heavy to move, but tripod mounted tubes are awkward to use compared to Dobs in my experience. Balancing heavy eyepieces is a pain with alt-az mounted telescopes on a tripod, but not a problem with a Dob with large trunnions. The former are also more prone to vibrations than the latter. There's a thread on SGL about someone struggling with eyepiece balancing on an ED80 mounted on a SkyTee 2. These issues largely go away with a well designed Dob.

Well, we just had one blue Moon last night and the next is March 31st, so you should be in luck.

No one has asked what sort of mount you're using that is so sensitive to balance, so I will. What mount are you using that gets thrown out of balance by a few extra ounces in the focuser? I'm using a DSV-2B alt-az mount, and it takes a 1.5 pound or heavier eyepiece to throw it out of balance. Anything 1 pound or less (all 1.25" Delos/XW/Morpheus/etc.) don't upset the balance enough to require adjusting the tube in the cradle. I do need to lock the altitude axis when changing eyepieces, but that's about it.

If the 25mm Starguider is as bad at the edges as the 25mm Meade HD-60, there is no way anyone with a 22mm LVW or 24mm Panoptic would be satisfied with its performance. There's a reason it doesn't cost $200+, and that reason is poor correction across the field. If it was as good as a Panoptic or LVW, who would buy those expensive eyepieces?

Kidney beaning (SAEP) is pretty much confined to negative/positive designs with poorly matched sections. The Nagler T1s and Radians both had it. The 6mm and 9mm Expanse type eyepieces have it, and most of the original Celestron X-Cel eyepieces had it. A positive-only design can't really produce SAEP. I'm pretty sure the Revelation to which you refer is positive only and so probably cannot have SAEP. You're probably just having issues with the long eye relief and large exit pupil as described by others here. I find sitting and keeping a light touch on the focuser or tube can help steady my alignment with the eyepiece's exit pupil to prevent blackout.

My favorite eyepieces for binoviewing are B&L Ultra Wide Field 31-15-74 eyepieces adapted to 1.25". Excellent eye relief, reasonably sharp to the edge, 60 degree field, and very easy to get your nose between them.

26mm Orion Sirius Plossls bought used for $20 each many moons ago.

To clarify, the 26mm plossls have the eye lens recessed so much that they're uncomfortable to use with eyeglasses. The 62 degree aspherics are just as sharp in the center 50 degrees as the plossls, and with the rubber eyecup removed, they are quite comfortable to use with eyeglasses. Sure, they fall apart a bit at the edge, but in binoviewers, you're more or less locked in to looking straight ahead to hold both view simultaneously, so that poor edge is in my peripheral vision where I can't resolve the imperfections.

At ~25mm, I use a pair of 26mm Plossls in my binoviewer. However, I prefer the view through my cheap 62 degree 23mm ebay-special eyepieces in my binoviewer.

50 degrees down to 9mm, then 45 degrees below that. That stiff rubber eyecup is very difficult to roll down. I've put a fingerprint on my 9mm LV eye lens multiple times trying to get it to roll down. Otherwise, it has very comfortable eye relief with glasses and is sharp right to the edge. However, using it after using my XL/Panoptic/XW/Delos/Morpheus/S-W/Nagler/ES-92 eyepieces gives me the feeling of chest tightness since an inky blackness closes in around the edge where there used to be image in the wider field eyepieces.

Apologies for veering off topic, but the UK sounds more and more depressing the more reports of clouds day and night I read about on here. My closest experience was travelling in Germany in June/July. It was overcast on all but 3 days out of 16 and never got above 60 degrees F. By contrast, it was sunny every day I was gone from Texas during that same time period, and the highs were always in the upper 90s.