Louis D

The only thing known to correct achromats for color is the long discontinued Aries Chromacor.

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

For planetary observation I like to be able to adjust precisely to seeing conditions. I use parfocaliser rings on the Delos 6 and 8 mm eyepieces so they match the XWs. On my C8 at F/10, I like to have closely spaced EPs to fine tune the magnification to the seeing. I would love to insert a 9 mm between the XW10 and Delos 8, if truth be told. I certainly find the jump from 203x with the XW10 to 290x with the XW7 too much. The 254x offered by the Delos 8 very handy. Under good conditions I can even use the 6mm at 338x, especially on Mars and the Moon. The XW5 is more useful in my faster scopes. 

I tend to use 1200mm and shorter focal length scopes.  I do have a 15" f/5 Dob that might make those closely spaced eyepieces useful, but I haven't used it in years since my back got messed up in an auto accident.

On 12/03/2021 at 11:31, michael.h.f.wilkinson said:

Another slight change, with an ES 17mm 92° EP replacing the Nagler 17T4 (leftmost EP, second row) 

The complete order of battle is: top row: Vixen LVW 42 mm, TV Nagler 31T5 "Panzerfaust", Nagler 22T4 (last T4 in the collection), UHC and H-beta filters, Orion Optics 2" Amici prism

2nd riw: ES 17mm 92°, TV Delos 14 mm, ES 12mm 92°, 2" dielectric star diagonal. 

3rd row: Pentax XW 10 mm, TV Delos 8 mm, Pentax XW 7 mm

4th row: TV Delos 6 mm, Pentax XW 5 mm, Denkmeier filter-switch diagonal 

I've got a similar lineup in my A-team case except that I don't have the Delos 6mm and 8mm eyepieces, or really anything in either focal length range aside from my 5-8mm SW zoom which has too little eye relief for me.  I've thought I might want something in those slots, but I find myself happily skipping from my 9mm Morpheus to my 7mm XW to my 5.2mm XL to my 3.5mm XW without feeling like I've jumped too much in any one step, except perhaps with the 3.5mm XW.

My question is, do you make much use of those those single digit Delos eyepieces?  Or do you prefer them and skip the XWs?  I'm thinking a 4.5mm Morpheus or Delos might get more use than either a 6mm or 8mm Delos.

Yes, Skywatcher prices, along with most astronomy gear prices, have gone up quite a bit.  Those of us in the US are now getting hit with a special 25% tariff on Chinese made items on top of those price increases, so consider yourself fortunate you're not having to deal with it as well.

If you can rig up a way to attach the camera in place of the scope, of course you can use the mount sans telescope.

It would definitely resist wind much better with a camera only due to not having a large sail of a scope tube attached to it.

Would the mount track more accurately?  Barely.  It will still have uncorrected periodic error (stars track small orbits) among other issues.  Again, keep the exposures short for later selection and stacking, and it would probably work well enough to learn basic astrophotography on.

SN 00007 makes it one of the first 10 produced.  That's a bit of a collectors item.

Enjoy!  Clear skies to you.

8 minutes ago, TheGlobeTrevor said:

Would a 1/2 focal reducer help?

Mathematically, yes.  Reducing image scale reduces the visibility of tracking imperfections.  I would avoid the cheap 0.5x focal reducers unless you're using a really small sensor.  They introduce all sorts of outer field aberrations like field curvature and spherical aberration.

Yes, I bought a dielectric 1.25" diagonal with a rigid case to safely hold the BV weight while minimizing the optical path length.  I normally use a 2" diagonal for mono viewing because I have so many 2" eyepieces.

1 hour ago, TheGlobeTrevor said:

Thank you to everyone I appreciate everyone's feedback. There are too many people to quote individually.

Except I will quote this one, this helps a lot because I live in Alberta.

Can someone help me understand why this Telescopes Equatorial mount with an (added) dual (or) single axis drive won't track properly for AP?

https://www.telescope.com/Orion/Orion-SpaceProbe-130ST-Equatorial-Reflector-Telescope/rc/2160/p/9007.uts?sortByColumnName=SortByPriceAscending

 

If you zoom in (using a mouse wheel) on the mount on Orion's website it looks like you can add a right ascension, and (I assume declination?) with a dual axis drive.

 

It's not that it won't track properly, it just won't do it accurately enough for long exposures.  You'll start to see stars wandering around a bit due to inaccurate tracking.  The mount also won't be able to resist gusts of wind, so you'll need to shelter it from wind somehow.  It would be fine for short exposures for later stacking.

Goto mounts will have field rotation which limits how long individual frames can be.

Off the shelf cameras won't be as sensitive to the far red where H-alpha resides as a dedicated astro camera would be.  It is an important nebula emission line for DSO imaging.

Here's a mega-thread on DSO imaging without an EQ mount:

Agree with @Highburymark about merging high power eyepieces in a BV.  The problem is that they expose even the slightest miscollimation of the BV.

I just use a pair of Celestron Regal 8-24mm zoom eyepieces with a 2x Barlow nose piece that yields 3x in the BV.  That way, I'm operating the zooms at 2.7mm to 8mm.  Absolutely no problems merging the images at any focal length, although I rarely go much higher than about 12mm natively (4mm Barlowed) on the zooms in this mode due to viewing conditions and exit pupil issues.

I also have no problems matching zoom focal lengths.  I zoom both roughly to where I want to be power-wise, tweak focus using my dominant eye if needed, and then fine tune the focal length of the zoom for my non-dominant eye until the images exactly merge.  It's actually easier to figure out best merge than best focus in my experience.

27 minutes ago, Deadlake said:

DSO's, aperture 76 mm. Presume you are thinking about travelling as you will need all the light you can get?

Small DSOs like globular clusters look really poor in ~75mm scopes.  There's simply not enough resolution to resolve them at 200x and above in my experience.

1 hour ago, Nicola Fletcher said:

I like planetary when there are planets to see, but would like to expand to DSOs within the limits of what these scopes will allow. I don't see myself getting anything bigger than the TSA120 so basically 3-5 inch refractors. 

Then I would invest in a binoviewer.  Even the entry level units are quite good.  I saw far more detail on Mars during this latest opposition with my Arcturus binoviewer and two 50 year old B&L microscope eyepieces than with any of my XL, XW, Delos, or Morpheus eyepieces in mono mode.  There's no substitute for using two eyes to pick out low contrast, fine detail.

8 hours ago, spartinix said:

The main advantage is faster switching between mono and binoview-mode, in particular for refractors and SCT's, IF used with Baader Quickchanger, T2-diagonal, and Clicklock eyepiece holder(s) and Baader ChangeRing (also dovetail-ring) for mono configuration.

Not seeing it.  I just pull the 1.25" diagonal and 2" to 1.25" adapter and binoviewer with associated OCS/GPC bits for reaching focus out of the focuser and replace it with a 2" diagonal and eyepiece to switch between modes.  On my Dob, I just pull the binoviewer and OCS/GPC bits out of the focuser and put an eyepiece in its place.

On my Mak without OCS/GPC focus help, it takes forever to move the mirror enough to reach focus with just a diagonal and eyepiece after pulling out the binoviewer.  Thus, I don't switch modes on it during an observing session.  I don't see how the quick changer would help unless it has an extension tube incorporated in it to match the backfocus of the binoviewer.

Am I missing something here?

4 hours ago, Basementboy said:

Great thread, thanks – does anyone have experience with the FPL-51 glass, for viewing (not astrophotography)? They're almost half the price of the 53 and I'm not sure I'd tell the difference just for visual. Any thoughts?

It depends on the magnification used.  At low powers, you're not likely to see any difference except perhaps on the brightest objects.  Where you will see it is at high powers where there will be a slight violet violet fringe around bright objects with FPL-51 that is much more subdued with FPL-53, especially in triplet form.  However, even the most APO refractor still has some fringing compared to a Newtonian at high powers.  If you've always used pure reflectors as I have, it's a bit of a surprise that the term APO doesn't equate to absolutely false color free, especially on either side of best focus as you find that best focus.  I would equate APO to very well tamed false color.  In a reflector, a white star is always white no matter which side of focus you're on by comparison.

I find 8x binos to be right at the limit for me to hand hold.  I need to be sitting with my elbows braced for 10x and above to get decent views.

If you're going to be standing, I would go with 8x42 bins.  Sitting, 10x50s will work.

Yep, I did the same thing several years ago,  except in reverse.  First, the 17mm ES-92 replaced my 17mm Nagler T4.  The next year, the 12mm ES-92 replaced my 12mm NT4.  Now if only ES would make a ~22mm version to replace my 22mm NT4. 😉  I don't think I'll hold my breath on that one happening any time soon, though.  I bought the 26mm Meade MWA to see if it could fit the bill, but it actually worked out to be closer to a 25mm Morpheus. 🙄 It's actually grown on me in that role once I'd adjusted my expectations for it.

If you like the 12mm ES-92, you'll love the 17mm version.  It's actually a bit better corrected at the edge, and a bit easier to hold the view in.

5 hours ago, osbourne one-nil said:

Sorry to raise an old thread but I'm finding it very hard to source replacement eyeguards for my 15mm and 24mm Panoptics. Anyone got any ideas?

Have you tried contacting Tele Vue in NY by phone?  I've read they can supply replacement caps, so they might also do eyeguards.

53 minutes ago, HollyHound said:

Agreed, I found the same when I had one... the 17.5mm doesn’t have the field curvature at all. To be fair the Pentax XW 14mm does also suffer in the same way. It very well maybe scope dependant though... longer focal lengths may be better 🤔

My old 14mm Pentax XL has worse field curvature than the 14mm Morpheus, and a narrower field to boot.  However, it is pin sharp and astigmatism free to the field stop once refocused.  The wider field and lesser field curvature of the Morpheus ousted my venerable XL from the spot it had held in my A-team case for 15+ years.  I decided I could live with the edge astigmatism since it was in a part of the field that doesn't even exist in the XL.  In all other ways, the two eyepieces were basically equivalent.

This is a great topic along the lines of the famous Meade 4000 Plossl threads.  How to distinguish early Japanese made from later Chinese made Celestron FRs.

2 hours ago, licho52 said:

My story.  Wasted 2 months and tons of aggravation.  Sky Watcher point blank refused to fix it.

Working as designed.  Never mind that the design (or implementation) is flawed.

37 minutes ago, andrew s said:

A dehumidifier caught fire. It was the only thing on as I was about to go on holiday. I had to damp the fire down before rushing to the airport.

Regards Andrew 

Not astro related, but it reminds me of my wife's workplace where the batteries in a UPS caught fire, destroying an entire server room.  She and a coworker actually fought down the flames using fire extinguishers brought to them from all around the building.  They managed to save the office building by keeping it out of the drop ceiling (the fire department arrived 15 minutes after the fire was out), but my wife was hacking up black soot for days.  The room was nearly an entire loss except for some backup tapes that somehow survived in their tape drives.  As a result of this fire, we will not use battery based UPSs inside our house.  There are flywheel based ones, but they are only made in enterprise class sizes ($100,000+ units).

If you're buying used, avoid the Meade FR unless you really know what to look for.  In the past, there was time when their FRs had optical issues.

The Celestron is a solid bet in the used market.  I've never read of any issues with them.

The Antares will be similar to the Celestron from what I've read.

The Starizona corrector is the one to get if you're very picky about image quality.

23 minutes ago, StuartT said:

forgive the dumb question, but as my new Morpheus has a wider angle of view, it actually has to squeeze more stuff in, so the image will actually be smaller than it otherwise would with, say, a 12.5mm Plossl?

So not really one to use on planets then? (as why would I want a smaller image?)

No, the central 50 degrees of the Morpheus will show the same amount of sky as the Plossl at the same magnification.  12.5mm focal length determines the image size.  You'll just get to see what was beyond the field stop in the Plossl for better context.

It should work fine on planets, especially for those of us without a tracking mount.  It gives more dwell time between nudges.

2 hours ago, Spongey said:

I feel like I certainly got a bad sample of the Esprit 100, as almost everyone else I've seen using it has excellent round stars. Rather than take the risk with a new copy though, I decided to go for another scope and see if that is any better (Askar FRA600).

The Askar is made by Sharpstar.  I have one of their 90mm APO FPL-53 triplets under the TS Optics brand.  Hopefully, your FRA600 works out better for you than the Esprit did.  I can say that I have spiky stars in my Sharpstar triplet until it acclimates, but I'm just a visual observer.