Louis D

I've sometimes seen thin wire loosely connecting the flotation triangles on large Dobs and had wondered what it was there for.  They're usually not strung particularly tightly, and now I know why.  It's just there to prevent gross rotation of individual triangles.

Of course, there's the famous Mars as big as the Moon to the naked eye during opposition email that stemmed from someone shortening this factual statement "At a modest 75-power magnification Mars will look as large as the full moon to the naked eye" to simply "Mars will look as large as the full moon to the naked eye" to make it fit the narrative style.  The original quote was apparently too wordy.

48 minutes ago, Barry-W-Fenner said:

Out of interest, what is the preferred mode to use these EP's in? 1.25 or 2"? Is there any advantages to using the morphs in  2"  mode.

I tend to use mine in 1.25 via the 2" to 1.25" click lock. However I Have considered
taking this out and just just my 2" click lock. With the 20mm spacer ring I Have just ordered I assume I should be able to achieve
focus OK in 2" mode. 🤔

When used in 1.25" mode, they're mostly parfocal with Pentax XL/XW, AstroTech AF70, ES eyepieces, and many others that focus at or very close to the shoulder of the eyepiece.  Using the 2" mode would require racking the focuser outward to compensate and would also result in poorer coma correction with the GSO CC.

5 hours ago, wibblefish said:

Good to know, thanks! Sadly with all the weird angles from neighboring buildings and streetlights in my garden it requires me to shift positions by a few meters if I need to move to what I want to observe though I guess I could do better planning and move less during the session! Food for thought certainly. 

You could make a dolly/trolley/buggy/cart for it with jacks at the corners.  You'd wheel it into position, and then drop the jacks to raise it off the wheels.  To move it, simply raise the jacks and wheel it to another location and drop the jacks again.  The jacks can even be used to help level the base on uneven terrain.

Something along the lines of this, but with a Dob platform:

4 hours ago, Barry-W-Fenner said:

Well after a look around I have just managed to get an M48 2" 20mm spacer ordered from Fleebay, Coming from China for £3.67...

I look forward to its arrival and trying out the CC & Morpheus combo!

Baz

Well, for that price it's worth trying out.  I think I paid about $25 for my 25mm spacer ring, so about a buck a millimeter.  Adapter rings and spacer rings are probably the most overpriced astro gear there is.

You can always pull an eyepiece up out of the eyepiece holder and retighten it to see if the additional spacing improves coma correction with a too short spacer ring.  You can't push an eyepiece further into the holder with too long of a spacer ring, so there is that advantage to the 20mm ring.

I use a TSFLAT2 with both my AT72ED and TS-Optics 90mm FPL-53 triplet to flatten their fields for visual use.  There is no change in their focal lengths.  I've seen images showing it works well for astrophotography as well.

Saturn is low even from Texas.  I was able to easily make out the Cassini division and a band on the night of July 30th when it was crossing the meridian in the middle of the night.  This was with an 8" Dob with an Arcturus binoviewer and 3x Barlow to reach focus with 15x microscope eyepieces.  Using two eyes helped immensely to pick out fine details.  I used the same setup at the Mars opposition to pick out fine details on it as well.  It wasn't as effective on Jupiter, though.  I was only able to pick out bands and a few dark barges on it.  The contrast was just too low for festoons or white ovals.  I tried some filters, but nothing helped much.

6 hours ago, Barry-W-Fenner said:

The cc sounds great fun, hope I Don't regret this purchase 😂

So the 1st thing I Need is the 19mm spacer.

Any suggestions for which rings will suit the Morpheus EP's.

Thank you all

I will agree to disagree with Don on the spacer length again.  I use a 25mm spacer to good effect with my range of eyepieces.  Most focus within 5mm of their shoulder and I get 95%+ of the coma corrected out without messing with the spacing on most of my eyepieces.  As I stated above, my 12mm NT4 is the only one needing parfocalization because it focuses 20mm from its 2" shoulder.  That's just too far off to work well with the GSO CC.  The uncorrected coma is intrusive without parfocalization.

Looks really similar to my 1998 vintage 2" Orion Deluxe 2x Barlow.

It wouldn't surprise me if Vixen was sourcing these for Orion during that period.  It's an excellent Barlow, just huge.  There should be a single light baffle about midway down the tube interior.

Check the optics end.  Does it look like this?:

2 hours ago, tooth_dr said:

I replaced it with an APM LZOS 105/650 and 0.75x Riccardi reducer. 

Just a wee bit more expensive.  Hopefully it's been working out for you.

The 3.2mm should be good for resolving globular clusters as well.  It's the only Paradigm (Starguider BST) I don't have, so I can't verify how good or bad it performs.  The 5mm performs quite well, though.  Not as good as my vintage 5.2mm Pentax XL, but still quite good.

4 hours ago, Barry-W-Fenner said:

Thank you Louis, This has raised more questions than answers. Its certainly put the purchase on hold until I find out more.

Do you have a link to the GSO model you have? I wonder if this would play nice in my 300p with the Morpheus EPS

bAZ

I forgot to mention that with the 25mm spacer ring in the GSO CC, I need 11mm of additional in focus which is quite manageable.

Also, immediately replace the shoddy screws with steel M4 cap head screws.  One of mine simply sheared off while tightening it on an eyepiece and I haven't been able to remove its remnants from the holder yet.

It used to be available as the Revelation CC in the UK/Europe, but I'm not seeing it listed any longer.

As @Sargares says above, it is available as Omegon in Europe and might be in stock.  Ping them about availability.

You could also try a wanted ad on (I think) Astro Buy Sell or even here on SGL classifieds.

In the US:

• Agena Astro in the US carries it as GSO, but is out of stock.
• Astronomics of Cloudy Nights fame carries it as Astro-Tech, but is also out of stock.
• High Point Scientific has it as Apertura, but is out also out of stock.
• OPT has it as TPO (the version I have, IIRC), but is out of stock.

There's also the Explore Scientific HR CC that requires 35mm of in focus and has an adjustable eyepiece holder.  It's also out of stock and quite a bit more expensive.

4 hours ago, Tenby2 said:

I was looking at the SWA series

http://www.opticstar.com/Run/Astronomy/Astro-Accessories-Telescopes-Opticstar.asp?p=0_10_5_1_8_320

probably just the 10,15 and 20mm eps as budget is limited.

There won't be much difference in performance between these and the aforementioned Svbony set at f/10.  Their 70 degree line is an introductory, budget wide angle line under the Bresser brand.  Opticstar is the JOC factory direct branding.

6 hours ago, Barry-W-Fenner said:

Hi all,

I am loking to purchase the attached Baader Coma corrector for my 300p to use in conjunction with my Morpheus EPS. I have a few questions if I may..

https://www.firstlightoptics.com/coma-correctors/baader-mpcc-visual-photographic-set.html

Is the coma corrector a permanent install on the scope or do you only use it when the need arises?

At the momnet I have a 2" 47mm clicklock on my scope with 2" to 1.25" clicklock reducer - This enabled me to do away with the standard 47mm extention provided with the scope. If I instal the CC will I need to do away with this combination or can I still use the clicklocks.  In fact I may do away with the 2" to 1.25 and use the Morphesus eps in 2" instead. Is there any benefit to doing this?

Will the CC change the focal length of my scope or does it just flatten the field?

Anyone have any experiance with this cc? Silly question but does it take away the slight comet shape I occasionally see of axis?

Thank you

Baz

My questions about this:

1. How much back focus is required for it?  I'm seeing ~55mm of spacing to the image plane, but that doesn't address in-focus.
2. If a lot of in focus is required, how do you insert it deeply into a 2" focuser with all those knurled rings hanging out?
3. How do you insert 2" eyepieces into a 1.25" holder?  Most CCs come with 2" eyepiece holders.
4. How much spherical aberration is introduced at high power?  Will you need to remove it to get the best image in the center at high powers?
5. How much does it flatten a curved Newtonian field?  It doesn't mention this at all.

Most folks in the past simply attached the MPCC to the 2" filter threads of low power 2" eyepieces with the appropriate amount of M48 spacer rings.  They didn't not use it as a general purpose CC.

The MPCC won't change the focal length of your scope, but I also see nothing about it doing any field flattening, only coma correcting.

I ended up getting the GSO coma corrector and added a 25mm M48 spacer ring between the holder and the optics section.  I parfocalized my 12mm Nagler T4 to work with it.  The rest of my eyepieces come to focus close enough to the eyepiece shoulder so as to not need parfocalization to get good coma correction.  The GSO mildly field flattens as well, which is a welcome benefit.  It does add some SA, so I remove it at high powers.

1 hour ago, globular said:

With a measured field stop of 21.7 that gives a calculated AFOV of 71 degrees.

So a measured FOV of 74 gives geometric distortion of about +4.2%.

Sounds fairly high…  ?

4.2% difference isn't all that unusual in wide fields.  The 35mm Panoptic has about 7% distortion, and it is highly regarded.

If it still provides decent views, consider yourself lucky and move on.  At $149, repairs are not economical if you can't perform them yourself.

1 hour ago, Deadlake said:

How Jerry would you get your 15” there? Quite a drive from snowy mountains in Canada?

Roadtrip indeed.  My wife and I just got back last month from a 1400 mile each way road trip to Michigan to visit her family.  That way, we got have our own car at the destination (rentals are hard to come by right now), had the opportunity to visit with other friends and family and attractions along the way, and avoided the maddening mayhem of American airports right now.  It doesn't hurt that we paid about $2.89/gallon for gas along the way, which is way cheaper than in Europe.

2 hours ago, Barry-W-Fenner said:

That location in Sacramento looks beautiful. Not a mobile/cell phone antenna in sight! Out in the middle of nowhere, Just a stunning clear sky and fresh air in your lungs!

I do admire the diversity and beauty of the US. No wonder only a small percentage of the US population have travelled abroad when you have such amazing locations to visit.

I compiled a list of over 500 of the places I've visited on trips around the US to give y'all some idea of how much there is to see within our contiguous borders.  I haven't even traveled the Pacific Northwest yet!

US_Destinations.pdf

17 minutes ago, jetstream said:

Roadtrip!😀

It would be a fun adventure- the USA is a great place to travel through and visit.

Now we just have to wait for the US guvmint to reopen the US to Canadians.  The Canadian government has already done this for vaccinated Americans.

6 minutes ago, jetstream said:

Ya but Louis- what about my ultra low premium 12.5mm Circle T that knocked my socks off viewing Jupiter last night in the 24" under very good seeing?😀

 

ps  shoulda had the TSA120 out to test go figure.

Now you're just making me jealous of your equipment and viewing conditions.  You could probably refer to your viewing conditions as ultra premium.  Part of the reason I want a retirement/vacation home in the Sacramento mountains of New Mexico.

28 minutes ago, jetstream said:

You still need a 17/14mm Nikon HW though! One of the "Super Premiums"

But sadly, not ultra-premium like the Masuyama line.  🤣

Just watch out for kidney beaning (SAEP) in the 6mm and 9mm eyepieces within the Svbony set.  Some folks are more sensitive to it than others.  Otherwise, they're well thought of at f/10 and even f/6.

3 hours ago, Ags said:

Nonsense - aren't those new Masayumas advertised as ultra premium?

Like ultra pasteurized milk as compared to pasteurized milk?   At least that's quantifiable.

From what I was able to find online, your scope has a 24% central obstruction by diameter, so it's a good compromise between being oversized and undersized.  There will be some light falloff if you were to try astrophotography, but since it's considered a visual only scope, that's irrelevant.  Some folks prefer visual only scopes with no larger than a 20% CO to maximize contrast at the expense of full illumination.

1 hour ago, Deadlake said:

1) Will I need a counterweight if a scopes around 13 kg. Presume this depends on the tripod used, Berlebach or T-Pod would be ok?

You want to keep the CG of the whole rig well within the footprint of the tripod feet.  I keep my tripod legs well spread apart under my DSV-2B mount to ensure this happens.  That's why I'm not a big fan of tripods legs that don't have variable leg spreaders.