324 replies to this topic

[Adam Long]

Thanks Don!

[f18dad]

According to Starman1: "...all the Morpheus use setting A and...the 17.5mm Morpheus (needs) a lower (TV in-focus) adapter."

[BGazing]

For the APM XWA HDC 20mm it's "A"

They are all parfocal, but does it change for shorter length EPs when you remove 2 inch skirt and, if it does, what is the setting?

[Starman1]

They are all parfocal, but does it change for shorter length EPs when you remove 2 inch skirt and, if it does, what is the setting?

For the Morpheus, :

The 2" skirt is not a skirt--it is a 2" machined section on the side of the eyepiece above the 1.25" eyepiece section.

The Morpheus cannot be used as 2" eyepieces in the Paracorr.  Setting H is not far enough out to bring the eyepieces to focus.

So the best bet is to use them as 1.25" eyepieces in setting A (actually, just a tad above setting A, but not quite up to level B).

The Paracorr adapter is 10.5mm tall.  If you were to use a shorter adapter, the Paracorr setting might be a bit higher up.

For the APM XWA, I agree with Dave on the 20mm.  The others I haven't paid attention.

 

I'll repeat here for those who missed it, if you have just ONE eyepiece for which you know the Paracorr setting, then you know the setting for all other eyepieces.

Insert the eyepiece for which you know the setting and focus the scope.  Then, without moving the focuser, insert any other eyepiece into the Paracorr and focus using the tunable top.

Whatever setting results, write it down--that is the setting for that eyepiece.

Don't be surprised if a lot of eyepieces are halfway between letters.  I record those on my lists as B+ or C+ to let me know.

Or, on the Paracorr II, the top moves so smoothly you can actually fine focus with the top.  In which case, you don't even need to know the settings of more than one eyepiece.

[DaleEh]

Does anyone know the Paracorr 2 setting for a Baader Aspheric 36mm? 

[Starman1]

Does anyone know the Paracorr 2 setting for a Baader Aspheric 36mm? 

Used as a 2" eyepiece, Baader shows the Reference Surface (focal plane) as being right at the 2" shoulder.

https://www.baader-p...hnical_data.pdf

 

That means setting E on the Paracorr VIP-2010, which is the focal plane of the Paracorr (2).

 

I will repeat here that you can find the setting of any eyepiece in the Paracorr that you don't know by inserting any other eyepiece whose setting you do know into the Paracorr,

dialing the correct setting for that eyepiece, then focusing the scope.  To find the setting for the eyepiece you don't know, at that point, merely requires inserting the new eyepiece and focusing the scope using the tunable 

top of the Paracorr.  Whatever setting puts the new eyepiece in focus is the correct setting for that eyepiece.

[Shinzawai]

According to Starman1: "...all the Morpheus use setting A and...the 17.5mm Morpheus (needs) a lower (TV in-focus) adapter."

C/Would you link the quote? Are we talking about the In-Travel Adapter here?

[Starman1]

C/Would you link the quote? Are we talking about the In-Travel Adapter here?

Yes.

To be technical:

The Paracorr adapter is 10.5mm tall.

An adapter of 8mm tall would parfocalize the 17.5mm Morpheus with all the others, since it needs to move in by 2.5mm.

I don't know of an adapter of that height.  Most vary from 9.5mm to 16.5mm.

So I used a TeleVue In-Travel adapter, in which the 17.5mm Morpheus sits on the lip of the adapter, which is 4mm tall.

So, since that is 4mm shorter than it needs to be to become parfocal, it needs to move out about 4mm from the other Morpheus eyepieces' setting in the Paracorr.

That is a mm shy of setting C in the Paracorr (i.e. 1mm closer to B).  I just usually focus it with the Tunable top, so achieving settings in between letters is easily done.

But if that adapter is used, you wouldn't be far off to use setting C if you wanted to pre-dial the top before the eyepiece is inserted.

[keityo]

OK, if you have a Paracorr, you don't have to ask.

If you have ANY other eyepiece whose position in the Paracorr you have optimized, and I'd bet you do, simply focus that eyepiece with the Paracorr in place,

then insert the new eyepiece and focus it using the tunable top.  Look at the setting on the side of the Paracorr--that's the correct setting for that eyepiece.

If you have even ONE eyepiece whose optimum position has been established, EVERY other eyepiece's perfect position can be found that way.

 

Everyone keeps asking what the optimum position is for this or that eyepiece, when it can be found in seconds without guessing.

 

The only issue might be if you do not have any TeleVue eyepieces and you have to start from scratch.

In that case, start with the Paracorr in its out-most setting, insert the eyepice and focus.  Look at the edge.  Still coma?  Move the Paracorr top in one position, focus, and

look at the edge of the field again.  Once, by experiment, you have found the optimum setting for that eyepiece--the one that yields no coma at the edge of the field,

then lock the focuser and find the optimum position for every other eyepiece you have by bringing it to focus using the Tunable Top on the Paracorr.

Record all the settings and you'll be able to pre-dial that setting the next time you insert the eyepiece.  You may still have to move the focuser a millimeter, but, basically,

you will have used the Tunable Top to par-focalize all your eyepieces AND optimize the com correction with each one.

 

Buy any new eyepiece and simply repeat to find its optimum position.  It isn't necessary to know the optimum position for any eyepiece before you buy it.

I noticed that there is a discrepancy on the paracorr 2 settings using this method and based on televue's recommended settings. For instance, after setting the 21E at position A (all the way in) and focusing, the 13E at position H is out of focus. Which ethos eyepiece / position is closest to optimal?
 

[Starman1]

I noticed that there is a discrepancy on the paracorr 2 settings using this method and based on televue's recommended settings. For instance, after setting the 21E at position A (all the way in) and focusing, the 13E at position H is out of focus. Which ethos eyepiece / position is closest to optimal?
 

I find the TeleVue settings are usually rounded to the nearest letter, not actually perfectly optimized.

Let's look at the Paracorr settings:

A is minus 0.4"

B is minus 0.3"

C is minus 0.2"

D is minus 0.1"

E is 0.0", the focal plane of the Paracorr.

F is +0.1"

G is +0.2"

H is +0.3"

 

TeleVue's eyepiece chart shows the focal plane of the 21mm Ethos is -0.38", which means it needs to move in 0.38".

Its ideal position would be 0.02" above setting A (0.5mm = 1/5 of the distance from A to B).  You can see why they say setting A is best.

TeleVue's eyepiece chart shows the focal plane of the 13mm Ethos is +0.27" (that is the 2" setting), which means it needs to come out 0.27" from setting E.

That is 0.03" below H, or 0.76mm closer to G = 3/10 of a setting inward from H.  You can see why they said setting H is best.

 

Suppose you set the 21mm at A and focus the scope, then pull the 21mm out, insert the 13mm, and focus the scope.

Where would the 13mm end up? The answer is 0.02 + 0.03" in from H, or 0.05 inward from H = 1/2 of a setting.  I would call it G-H or G+.

The result is that the 21mm is 0.02" away from its ideal position and the 13mm is 0.02" away from its ideal position.

And that is negligible and unimportant for coma correction.

 

Now, you could do what I do and simply use the tunable top as a focuser.  I don't even pay attention to the letter that results--I'm in between letters most of the time.

But, I think it's quite safe to simply use the letter that TeleVue recommends (the 17mm T4 should be setting E--one error in their chart) and simply refocus the scope a small fraction of a mm.

That's one of the reasons I've said that with a Paracorr you will need about a +/- 1mm travel in the focuser.

 

So, when finding the correct setting for an unknown eyepiece, round off to the nearest letter.  That will be accurate enough.

[TayM57]

I find the TeleVue settings are usually rounded to the nearest letter, not actually perfectly optimized.

Let's look at the Paracorr settings:

A is minus 0.4"

B is minus 0.3"

C is minus 0.2"

D is minus 0.1"

E is 0.0", the focal plane of the Paracorr.

F is +0.1"

G is +0.2"

H is +0.3"

 

TeleVue's eyepiece chart shows the focal plane of the 21mm Ethos is -0.38", which means it needs to move in 0.38".

Its ideal position would be 0.02" above setting A (0.5mm = 1/5 of the distance from A to B).  You can see why they say setting A is best.

TeleVue's eyepiece chart shows the focal plane of the 13mm Ethos is +0.27" (that is the 2" setting), which means it needs to come out 0.27" from setting E.

That is 0.03" below H, or 0.76mm closer to G = 3/10 of a setting inward from H.  You can see why they said setting H is best.

 

Suppose you set the 21mm at A and focus the scope, then pull the 21mm out, insert the 13mm, and focus the scope.

Where would the 13mm end up? The answer is 0.02 + 0.03" in from H, or 0.05 inward from H = 1/2 of a setting.  I would call it G-H or G+.

The result is that the 21mm is 0.02" away from its ideal position and the 13mm is 0.02" away from its ideal position.

And that is negligible and unimportant for coma correction.

 

Now, you could do what I do and simply use the tunable top as a focuser.  I don't even pay attention to the letter that results--I'm in between letters most of the time.

But, I think it's quite safe to simply use the letter that TeleVue recommends (the 17mm T4 should be setting E--one error in their chart) and simply refocus the scope a small fraction of a mm.

That's one of the reasons I've said that with a Paracorr you will need about a +/- 1mm travel in the focuser.

 

So, when finding the correct setting for an unknown eyepiece, round off to the nearest letter.  That will be accurate enough.

What I've done is use my A11 as my reference eyepiece since the setting for the A11 is A, so it's easy to remember. The setting for my DeLites is D, again easy to remember but I don't bother with setting the PII to D for the DeLites. I just set the PII to the A setting, focus with the A11 and then use the turntable to focus the DeLites. I don't touch the focuser unless I need really fine adjustment.

 

Similarly, I know to always pair the PII with my eyepieces, so if I'm using the PM, that goes into the focuser first. The PII stays with the eyepiece, always.
 

[eblanken]

Hello TayM57 and all,

 

I just learned (I think) that Steve Swayze is no longer living among us (from Tay's signature).

 

I am saddened by this news.

 

RIP Steve.

 

Man do I feel out-of-touch !!! Wow, Steve was younger than me, so that hits me (perhaps) harder than some people.

 

Ed (aka eblanken) Blankenship

 

P.S. Thank you Tay for bringing me up-to-date.

 

P.P.S. Tay, PM me if you want. I remember meeting you & buying a nice set of Pentax XW eyepieces from you. I still have them.

Edited by eblanken, 24 July 2022 - 11:36 PM.

[TayM57]

Hello TayM57 and all,

 

I just learned (I think) that Steve Swayze is no longer living among us (from Tay's signature).

 

I am saddened by this news.

 

RIP Steve.

 

Man do I feel out-of-touch !!! Wow, Steve was younger than me, so that hits me (perhaps) harder than some people.

 

Ed (aka eblanken) Blankenship

 

P.S. Thank you Tay for bringing me up-to-date.

 

P.P.S. Tay, PM me if you want. I remember meeting you & buying a nice set of Pentax XW eyepieces from you. I still have them.

Hi! I remember you! I felt so dumb driving off with the back hatch door open! Hahaha... I'll send ya a PM!

[eblanken]

Hi! I remember you! I felt so dumb driving off with the back hatch door open! Hahaha... I'll send ya a PM!

Hi Tay,

 

It was a good day from my perspective: I got a full set of Pentax XWs in a nice Yellow Harbor Freight Case at a good price !!!

 

Thank you for honoring Steve in your signature and in your enjoyment of his mirror !!!

 

Ed

 

P.S. PMs received and replied back as well.

[Starman1]

What I've done is use my A11 as my reference eyepiece since the setting for the A11 is A, so it's easy to remember. The setting for my DeLites is D, again easy to remember but I don't bother with setting the PII to D for the DeLites. I just set the PII to the A setting, focus with the A11 and then use the turntable to focus the DeLites. I don't touch the focuser unless I need really fine adjustment.

 

Similarly, I know to always pair the PII with my eyepieces, so if I'm using the PM, that goes into the focuser first. The PII stays with the eyepiece, always.
 

Is that setting for the A11 as a 1.25"?  Because TeleVue says the setting for the A11 is C as a 2".

I've verified that by setting the top to B for the 22mm Nagler and then focusing the A11.  It ends up at C, but I am using it as a 2" eyepiece.

[TayM57]

Is that setting for the A11 as a 1.25"?  Because TeleVue says the setting for the A11 is C as a 2".

I've verified that by setting the top to B for the 22mm Nagler and then focusing the A11.  It ends up at C, but I am using it as a 2" eyepiece.

Oops... Yeah I use the A11 as a 2". Setting C from now on it is...

[eyeoftexas]

I've scanned through this thread and did not see any notes for the Nikon Nav-12.5HW with and without the EiC-10 in a Paracorr 2.  I apologize if I missed it, but can someone tell me if it is known?  Is it with the 2" skirt on, or in 1.25" form?  Thanks.

[Starman1]

I've scanned through this thread and did not see any notes for the Nikon Nav-12.5HW with and without the EiC-10 in a Paracorr 2.  I apologize if I missed it, but can someone tell me if it is known?  Is it with the 2" skirt on, or in 1.25" form?  Thanks.

In other threads, the 12.5mm is seen to have its focal plane at or very near the shoulder of the eyepiece as a 2".

That would use setting E on the Paracorr 2 or the middle line on the Paracorr 1.

I could not find information about its setting when used as a 10mm.

 

However, one of the points I've made a few times in this thread is that you don't have to ask what the setting for any eyepiece in the Paracorr is if you have just one

eyepiece for which you know the setting.  You simply insert the eyepiece you know the setting for and focus the scope.

Remove that eyepiece and insert any other eyepiece from any company into the Paracorr and focus using the tunable top of the Paracorr.

Whatever setting that you get is the setting for that eyepiece.  You can pre-dial that setting in the future before you insert that eyepiece, and it will be in its optimized setting.

[eyeoftexas]

Thanks, Don.  The reason I asked is that my Dob with the PC2 is two hours away, and it's been cloudy for weeks.  I know how to find the setting, but wanted to know ahead of time so I can just use the eyepiece when (and if) I can get out there again.

[suburbanastro]

I set my Paracorr type II at A when I use my 31mm Nagler and then focus until the stars are nice and sharp. I then focus my 10mm Ethos by turning the Paracorr to H. But unfortunately the Paracorr won't bring my 6mm Ethos to focus whether I use it as a 2 inch eyepiece or if use the 1 1/4" adapter that came with the Paracorr. Am I missing something ?

[Adam Long]

According to TV it should focus at B with the ‘hi-hat’ 1 1/4” adapter. Which adapter have you got?

[suburbanastro]

The only adapter I have is the 1 1/4" one that came with the Paracorr. I guess I need I need a hi-hat then. Thanks for your reply.

[Starman1]

The only adapter I have is the 1 1/4" one that came with the Paracorr. I guess I need I need a hi-hat then. Thanks for your reply.

The adapter that comes with the Paracorr is fine for use of the 6mm Ethos at setting B.
I use the 6mm at that setting. It is 10.5mm tall.

Edited by Starman1, 22 February 2023 - 09:52 PM.

[suburbanastro]

The adapter that comes with the Paracorr is fine for use of the 6mm Ethos at setting B.
I use the 6mm at that setting. It is 10.5mm tall.

Thanks Don!

[Gschnettler]

I’m going to try my Paracorr 2 for the first time tonight. I read through as many of the previous posts as I could. Am I correct with these settings?

APM UFF 30 - G
Morpheus 12.5 - A+
Morpheus 9 - A+
Pentax XW 7 - A
Pentax XW 5 - A

And what about these eyepieces?

APM UFF 24 -??
APM UFF 18 - ??