Louis D

23 years, and I've yet to deem my Dob's mirror dirty enough to need cleaned.  It's always been stored with tight caps at both ends and just the center hole in the Rigel Aline cap in the focuser to allow a bit of air in and out.  It's always been stored at the back of a coat closet that is rarely opened (don't need heavy coats in Texas very often).  The enhanced mirror coatings look fine as well.

What about for silicone glued primaries?  Is it worth cutting the factory glue, cleaning it all off both the mirror and cell, and then trying to reglue it with hopefully the same type of silicone glue?

2 minutes ago, johninderby said:

Just a simple single shot image using my StellaMira 80 f/10 but glad you like it. 👍🏻👍🏻👍🏻

 

Here's an effort of mine from nearly 20 years ago with a 2002 Olympus C4000, a 14mm Pentax XL, and my 8" Dob:

And here's a Mercury transit with a DSLR at prime focus with a GSO CC and the same scope:

So, if you're just interested in solar and lunar, you can get pretty decent shots with really basic, nontracking equipment.

3 hours ago, MrFreeze said:

I would always prefer an EQ even for purely visual use. It's too much of a faff to twiddle with two slow motions. So much easier on a driven EQ, even if Polar alignment is only approximate. And if you're trying to show someone something at high magnification, it's invaluable.

David

If EQ mounts didn't require counterweights and were as rock stable pound for pound as Dobsonian mounts, I would agree.  I did try to build my own EQ platform years ago, but it introduced too much flex for my liking.

7 hours ago, F15Rules said:

Interesting stuff John..

It could be that the second generation Meade UWAs had improved coatings..

I'm wondering though whether 20 or so years ago the polish of Japanese made EPs made up, at least partly, for any coating deficiencies? This might back up Don's assertion in your quoted thread, where he says "The fact that a ten inch reaches over 0.4 magnitudes deeper than an 8" shows how little effect transmission in eyepieces has. Probably of more importance are factors such as the spectrum of transmission and the polish quality on the glass."

I think that modern coatings application technology, wherever EPs are made now, including China and especially Taiwan, is to an exceedingly high standard, which is to all our benefit of course..

Dave

As I've reported elsewhere, the original smooth sided Meade 4000 UWA 14mm is very well corrected across the field.  Really remarkably well considering it's nearly 40 years old.  However, it's control of stray light is abysmal.  As the moon is panned around the field, there are all sorts of glares and reflections that are completely absent in the 14mm Morpheus and 14mm Pentax XL.  I'll have to have a look through the top and bottom lenses with a bright light to see what's going on inside.

Red has been the go to star party color for years, and you would be hard pressed to convince the powers that be that any other color would be better.

I just prefer an incredibly dim white light when observing alone because it causes less eye strain.  Under my Bortle 5/6 skies, it's not like it's pitch dark out anyway.

I picked up a 90mm TS APO FPL-53 triplet in 2019 just to see what they're like.  I was shocked to find out it takes about 30 minutes to cool down or warm up just 10 degrees F.  That's as slow as my very open 8" Dob!  Mars views were very sad compared to the 8" Dob as well, to say nothing of resolving GCs.  Aperture is king.

I'd spend the money on an 8" or 10" Newt with a mirror hand figured to 1/20th wave (think Zambuto or similar) if you want the finest planetary details.

3 hours ago, John said:

Plus an handling charge of £8 or so I think. That was the 25% that I was on about.

 

I've never gotten hit with handling fees importing into the US because I've stayed under the $800 limit.  I've heard UPS and other private shippers charge a usurious percentage of value "brokerage" fee to clear customs, so I tend to avoid them on international shipping.

55 minutes ago, Adam J said:

For what scope?

For visual or imaging?

Have you caractroised how bad the CA is?

Adam

Old thread resurrected.  OP is long gone from this thread.

1 minute ago, Jiggy 67 said:

No , VAT pluss 2.5% duty to pay on arrival

At least that's cheaper than US duties on optics of 8% for valuations over $800.

6 minutes ago, Jiggy 67 said:

Just ordered from Astronomics in the US, thanks @Louis D.........free shipping!!....strangely,  so total cost - £145, £10 cheaper than UK!!.....bit nervous really, never ordered from the US before

Let us know if you get hit with VAT and import duties.  I think the US decided that the cost of the bureaucracy it would take to check every last package entering the US would far outweigh the revenues collected.  That, and individual states would have to figure out how to collect sales tax since the federal government is not responsible for collecting state taxes.

4 hours ago, Jiggy 67 said:

£155 now with a 40-60 day wait from FLO. I’ve looked everywhere on the internet, it’s surprising how few retailers sell them and those that do haven’t got any stock, RVO told me no chance for a couple of months!!! It’s ok, I’m a patient guy and it will arrive when it arrives and it will cost what it costs 😀

I don't know how the reverse works, but I like buying from the UK because the retailers don't collect the appropriate state sales tax like US retailers do, and they don't charge UK VAT against me.  That, and as long as the value is under $800, there's no import tariffs.  Plus, the USD has been fairly strong against the GBP for the last few years.  Shipping on small items like eyepieces isn't too bad from the UK to the US, either.

Here's mine in Texas:

We had high, thin clouds and a full moon last night, and temps in the low 40s.  I'd have gone out, but I had had an exhausting day at work yesterday.

On 19/01/2021 at 09:28, johninderby said:

Why would you want to carry it outside in one go? 🤔

So easy to carry both parts in two trips.

Because I'd have to disconnect the DSC cables and then realign the altitude DSC arm with its peg on the base which isn't as simply as you'd think while dropping the tube assembly on the base.  The whole thing is under 50 pounds, so no worse than carrying softener salt bags.

Astronomics (CN sponsor) just got the 24mm ES-68s back in stock.  Hurry if you want one.

27 minutes ago, Jiggy 67 said:

Only problem is there is a bit of a wait for these to come into stock.

If memory serves me correctly, the 24mm ES-68s were often in short supply long before the lock downs put everything in short supply, so be prepared for a long wait.

So no off axis coma then?

45 minutes ago, michael.h.f.wilkinson said:

Unlikely, the main optics are very different.

So, are there dedicated correctors for classical Cassegrains?

Do Newtonian coma correctors work in classical Cassegrains?

You've probably already read Bill Paolini's 24mm-26mm eyepiece comparison article during your research, but it in case you haven't, it's worth a read.

I just keep my Synta 127 Maks in padded camera bags or wrapped in bubble wrap and placed in a gym bag.

2 hours ago, Connor brad said:

Should the explore scientific coma corrector work in my scope? 

When you have reached focus with your most inward focusing eyepiece, measure the distance the focuser tube has left to travel inward.  You'll need ~35mm of inward travel to reach focus with the ES as I said above.  My Dob's low profile focuser has only about 20mm of inward focuser travel left with most of my eyepieces, so it wouldn't work for me.

I'm assuming that since your scope claims to be optimized for photography, it has at least 55mm of back focus available for T-ring attachment of DSLRs:

                Also the tube length has been slightly shortened to optimize performance for prime-focus photography

16 minutes ago, Connor brad said:

although I got a 27mm panoptics, 18mm celestron xcel and 12mm bst starguider since I have a televue eyepiece is it only the paracorr that works on televue eyepieces or can I use any coma corrector with it? 

Yes, you can use any coma corrector with any telescope and any eyepiece.  However, if you had an f/4 or faster Dob, I would definitely recommend the Paracorr II.

I use the GSO/Revelation coma corrector with a 25mm spacer between the optics section and the eyepiece holder.  As long as all your eyepiece focus within about 5mm of the eyepiece shoulder, I've not found a need to tune the distance for each eyepiece.  For me, eliminating 95% of the coma is good enough.  It does require about 11mm of in focus, so it is similar to the Paracorr II.

The ES HR corrector requires about 35mm of in focus, so not all scopes are able to achieve focus with it.  Most reviews of it are positive aside from the very find threads to tune correction.

About 50% of nights are clear enough to do some sort of observing around this part of Texas.  However, the seeing conditions may not be the best due to dust having been blown in by a recent front, or having high winds due to severe pressure gradients between high and low pressure systems.  I'd say about 20% to 25% of nights are decently usable (including those with the moon shining brightly) taking these issues into consideration.  This doesn't even take into consideration the mosquitos ruining most summer nights. 😁