Louis D

4 hours ago, TheLookingGlass said:

The eye relief on the 20mm XWA is good enough if you want to use glasses. I tried that and it works. My glasses rest against the folded rubber eye guard. It's super immersive and perfect in the coma corrector.

Since the eye lens is about the same diameter for both (~30mm), I wouldn't doubt you would be able to see at least as much of the field in the XWA as in the NT4 (~82°) while wearing eyeglasses.  However, can you actually see the entire 100° of the XWA with eyeglasses?  I can just take in the 92° field of my ES92s by resting my glasses against the folded eye guard of each, and they each have a 43mm diameter eye lens!  I tried an Ethos at a star party while wearing eyeglasses and could only see the inner 70° or so with ease, and it also had a ~30mm diameter eye lens.

I'm investigating a theory of mine that thread depth is also a factor.  I've noticed on closer inspection of some troublesome male filter threads that they are deeper and sharper compared to less troublesome threads which are shallower and blunter.  I think it's because a lot of female filter threads are not very deep on inspection.  Thus, the male threads have to "chase" the female threads to make them deep enough to thread into.

4 hours ago, Ian McCallum said:

28 inches, but the base of the dob is 25.5 inches. I'm in the UK, so US building codes don't apply. 

I'm guessing there's no ADA (Americans with Disabilities Act) equivalent in the UK dictating such things nationwide.  Getting a wheelchair through a 28 inch doorway would be a serious challenge.  Getting a washer/dryer set through that door would also be tight.

16 minutes ago, Tiny Clanger said:

There's a lot of love for a filter called a Baader Neodymium (my spelling may be a bit approximate there)  , apprently it increases contrast in all manner of things, but it costs around £60 ...

It's basically the same thing as the generic Moon & Sky Glow filters that go for under $20.  Just do your homework and look for the pale blue filter color and the spectral chart.

If you watch the classifieds, you should be able to pick up a used 2" GSO (Revelation, TPO, etc.) dielectric diagonal for under $100.  A 2" SCT visual back generally goes for under $30.  You won't be able to use your R/C with them due to vignetting.  Is it worth the upgrade, that's a question only you can answer.  The true field of view with a 32mm Plossl and R/C is about the maximum possible with an SCT already.

I'm puzzled why you have both 30mm and 35mm ED eyepieces.  At the low end of the power scale, there isn't a whole lot of difference between them.

I am also puzzled why you don't have more eyepieces at the shorter focal length end.  You could do with a 4.5mm to 5mm eyepiece as well as a 9mm to 12mm eyepiece to fill in some of the gaps.  I suppose you've been using your 2.5x Barlow to fill these roles?  How often do you find yourself using it for higher powers?  If it is a lot, I highly recommend getting a dedicated eyepiece in that range (or ranges).

The BH would do okay with the SCT but not with the Dob.  I'd stick with Morpheus, Delos, or XW eyepieces for the Dob's sake.

How narrow is your front door?  Most construction codes dictate a minimum 32 inch wide front door; however, most are 36" wide.

I would think vintage American made SCTs from Celestron and Meade would both be higher priced in all of Europe than in the US during the first sale in the same way Tele Vue eyepieces are consistently more expensive in Europe than the US.  This initially higher price then continues over to the used market.  I'm also going to guess that SCTs didn't sell in as high a numbers over there as they did here, so the used market isn't so flooded as here, driving up used prices in Europe as a whole.

4 minutes ago, Basementboy said:

Any idea what the glass would be on this scope? 

I would think well annealed "float" glass.  At their original price point, you weren't going to be getting Pyrex, Quartz, or Sitall glass.

Some deluxe SCTs intended for imaging may have come with Crown glass correctors.

Pistol cases are pretty cheap in the US, but probably harder to come by in the UK.  I have several for binoviewers and smaller eyepieces.  They're not waterproof, but they're good enough for my less expensive eyepieces.

I use Pelican style waterproof cases for my more expensive eyepieces.  There are some decent Chinese made knock-offs available, just with lower density foam.

On 09/10/2021 at 03:23, mareman48 said:

I actually bought the same or similar model a few weeks back, my second scope.

 

Always wanted this model so my children can use it, mine was actually brand new boxed, belonged to an old boy who kept it in storage and never used it.

The exact model is Meade LX10 EMC 8" 

What a gorgeous conversation piece.  Those lines were classic.

39 minutes ago, Basementboy said:

Shame. I find it to be much nicer in many ways – smoother action, more reassuringly solid, generally high levels of attention to detail – than some of the newer scopes I've seen!

Preaching to the choir you are.  You're comparing classic American manufacturing to modern Chinese manufacturing.

2 minutes ago, Don Pensack said:

Collets do really well on eyepieces with smooth barrels, but not eyepieces with conical tapered undercuts.  On those, the simple thumbscrew works best because the thumbscrews pull the eyepieces down into tight contact with the top of the 

eyepiece insertion tubes.  Ideally, a centering binder would be best, but centering binders don't work well on eyepieces with barrel undercuts.

Or any undercut if the collet is high as with the Arcturus.  It tends to push the eyepiece up and out of the holder because it's trying to tighten on the upper taper.  I have to jam it down while tightening to prevent this from happening.

Even with thumbscrews I've had this issue (on a diagonal) when it is too high and also pushes the eyepiece up and out while tightening because it's pushing against the upper taper.  I don't know how high the Norin BV thumbscrews are mounted, though.

3 hours ago, mikeDnight said:

I never use the diopter adjustment as it demerges the image.

Same with the Arcturus BV.  It's actually funny in a sad sort of way to watch one image circle around the other while spinning the diopter adjuster.

1 hour ago, TheLookingGlass said:

Seems like an ongoing problem with these. 🤨

I'm picturing the coatings were made from agar (think Petri dish lining).

On 10/10/2021 at 06:03, HiveIndustries said:

 

So, grass is always greener my friend. I'm in the shadow of the lights of NYC at a solid Bortle 9. I'm lucky enough to have a double lot but pollution from neighbors is that 10x literally. I gotta battle my own families bathroom light and kitchen lights even!

All that means is I've been limited to planets and lunar for the time being and traveling to dark sites is going to be my future.

There's nothing wrong with dwelling on these things as a newb though, they're kind of absolutely mind blowing and one could spend a lot of time just looking at them for years.

Have you looked into getting an observing hood to block local stray light?  Even a black towel covering your head would help.

8 hours ago, vlaiv said:

https://www.firstlightoptics.com/equatorial-astronomy-mounts/asterion-ecliptica-light-tracking-platform-for-dobsonian-telescopes.html

Obviously aimed at the Euro market since the majority of the US lies between 25° and 47° north latitude.

I've found a laser collimator best for aiming the secondary at the center of the primary.  It's also handy to align the primary back to the secondary with a truss Dob while crouching at the back of the primary mirror.

A sight tube or cheshire is best for centering and squaring the secondary below the focuser.

I prefer to use a Rigel Aline to align the primary back to the secondary/focuser, assuming it is center marked with a donut ring.  It also makes for a handy focuser cap, leaving just a small vent hole to allow the OTA to breath in storage.

Just make sure the BV you choose has locking collets instead of thumbscrews.  Because the latter push the eyepiece off center to the side, merging can become an issue with them.

I have the Arcturus BV with two useless Barlows (both induce the weirdest linear instead of radial coma) but without the eyepieces of the current version.  I've never had trouble with the locking collets with smooth side eyepiece barrels.  I use the nosepiece from a Meade 140 2x Barlow to reach focus, operating at 3x.

I also tried inserting my BV into a Parks GS 2x Barlow (also known as Celestron Ultima and Orion Shorty Plus) and saw pretty much identical performance, so there are multiple options to reach focus.

On 06/10/2021 at 13:34, Don Pensack said:

Hmm.  I measured those two eyepieces and got 49.8° on the Sirius and 49.5° on the GSO.

My GSO also had a field stop <27mm, so it's possible they're changed the eyepiece over the years.  That was ~2010.

I just measured the Sirius and GSO 32mm Plossl field stops directly using digital calipers after unscrewing each lower barrel to get clear access them.  I got 27.2mm for the former and 27.1mm for the latter.

I then did a comparative photographic analysis of each to the 27mm Panoptic accepting TV's 30.5mm FS diameter as gospel and arrived at 27.1mm for each.

At no point was there a doubt that they have at least a 27mm diameter field stop diameter, the only quibble would be about that last 0.1mm.

7 hours ago, Deadlake said:

The clear aperture is the thing, which limits what EP's you can use.

There is a downside to larger clear aperture, and that is larger prisms (or mirrors) which require more available in-focus due to longer optical path length.

I've discussed binoviewers with some CN folks who have used several different high end binoviewers, and the main differences are in clear aperture size, mechanical construction, and accessories.  Image quality doesn't vary much, so entry level BVs are just fine for planetary viewing.

Try it out, see what the image looks like, and report back on here.  What's the worst, the view is terrible?  Take a medium bright star at low power and sweep it from center edge and watch what happens to its shape and focus point.

I often mix and match optical pieces looking to find hidden gem combinations.  One is using the Tele Vue Panoptic Barlow Interface with the GSO 2x 2" ED Barlow.  They work perfectly together.  I also tried the PBI with a 6" long Orion Deluxe 2" Barlow from Japan.  Horrible results probably due to the massive mismatch in expected focal length.  The TV Big Barlow that the PBI was intended for has a fairly short focal length like the GSO.

You could skip a step and order pre-cut ProtoStar FlockBoard in the size closest to your Newtonian's tube.  It just snaps into place, no adhesive required.

4 hours ago, Peter_D said:

I have a de-forked Meade 2080 dating from the mid 1990s. SCT prices are be a lot higher in Germany than the UK or especially the US!

Probably because the market here was saturated with them during the 1980s and 1990s in particular.  8" SCT OTAs from that era regularly go for about $300.  I think it's a perception that they're old and not worth as much as something shiny and new.

16 minutes ago, mikeDnight said:

Vixen LV's and LVW's are special too, but are also nolonger in production.

Good point that the 7mm LV was discontinued in the NLV and SLV lines.  I believe the LVW had an 8mm rather than a 7mm.