324 replies to this topic

[rjacks]

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 - ??

I find the optimum setting for the Pentax XWs is between A and B on the Paracorr2. As discussed previously, all you need to know is the paracorr setting for one of your eyepieces, focus with it, and then use the Paracorr adjustment to rough focus every time you change eyepieces.

[Gschnettler]

Regarding this:

“As discussed previously, all you need to know is the paracorr setting for one of your eyepieces, focus with it, and then use the Paracorr adjustment to rough focus every time you change eyepieces.“

The problem is that I don’t know the Paracorr setting for any of my eyepieces. Now I know that Pentax XW should be somewhere between A and B. Should I just set it to that, focus with a Pentax and then figure out the rest from there?

I’m a little concerned about trying to use the Pentax eyepieces as the anchor since all I have is 5 and 7mm and so they zoom in a lot with my 12” dob. And the seeing is supposed to be poor tonight so under those conditions I wouldn’t even be using these eyepieces. What I’m trying to say is that it might be tough for me to get precise focus with these eyepieces tonight.

Any additional information regarding how to approach this with my eyepieces would be much appreciated!

[Starman1]

Regarding this:

“As discussed previously, all you need to know is the paracorr setting for one of your eyepieces, focus with it, and then use the Paracorr adjustment to rough focus every time you change eyepieces.“

The problem is that I don’t know the Paracorr setting for any of my eyepieces. Now I know that Pentax XW should be somewhere between A and B. Should I just set it to that, focus with a Pentax and then figure out the rest from there?

I’m a little concerned about trying to use the Pentax eyepieces as the anchor since all I have is 5 and 7mm and so they zoom in a lot with my 12” dob. And the seeing is supposed to be poor tonight so under those conditions I wouldn’t even be using these eyepieces. What I’m trying to say is that it might be tough for me to get precise focus with these eyepieces tonight.

Any additional information regarding how to approach this with my eyepieces would be much appreciated!

If you do not know the Paracorr setting for any eyepiece, here is what to do:

 

Place an X over the 2" opening of the Paracorr, crossing in the center, with translucent scotch tape.

Set the Paracorr to setting E.

Point scope at the Moon and focus the moon on the tape where it crosses.

Wear your glasses if you need distance correction.

Either lock the focuser or simply don't touch it for the next operations:

 

Remove the tape, insert any eyepiece, and focus the eyepiece using only the Tunable top of the Paracorr.

Note the setting that puts the eyepiece in focus.  Write it down--that is the setting for that eyepiece.

Repeat with every eyepiece you own, and write down their settings.

Now, in use, in the field, you will "pre-dial" that setting of the eyepiece before inserting it.

 

Or, you can set just one eyepiece and focus all other eyepieces using the Tunable Top.

Either way, you will optimize the coma correction for every eyepiece.

[rjacks]

The setting for the APM 30mm UFF is G. You can start there.

[Jack Day]

Hello,

 

Is this chart and picture correct for the Paracorr type 1.

 

I updated the position numbers based on Don P's comments earlier in the thread.

 

Thanks

Attached Thumbnails

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[Starman1]

Hello,

 

Is this chart and picture correct for the Paracorr type 1.

 

I updated the position numbers based on Don P's comments earlier in the thread.

 

Thanks

Looks good.  1 is all the way up, 5 is all the way down.

Note that ** means the eyepieces are used as 1.25", and *** means the eyepieces are used as 1.25", but the setting still isn't correct(10mm and 13mm Ethos are best used as 2')

If the 3.7mm and 4.7mm Ethos are used as 2", with their provided adapters, they would use setting 1, the same as the 10mm and 13mm Ethos when they are used as 2" eyepieces.

If the 6mm and 8mm are used as 1.25", they would likely use a different setting that TeleVue's other 1.25" eyepieces, but I have not used the flat top adapter with them.  I cannot verify setting 4 would be correct.

[25585]

Does screwing filters to eyepieces affect Paracorr settings much or at all? What tolerance is there in Paracorr for that?

[Starman1]

Does screwing filters to eyepieces affect Paracorr settings much or at all? What tolerance is there in Paracorr for that?

No, a filter won't affect the Paracorr settings at all unless threaded to the eyepiece, and then, typically, about 1/4 wave, or a tiny fraction of a Paracorr setting.

The Paracorr provides pretty much the same correction with a +/- 1mm at the focuser, and a filter changes the focal point a lot less than that.

So what most people do is to use the same eyepiece Paracorr setting and merely refocus the scope when a filter is used.

[hbrunet181]

Hi Folks, 

 

Anybody have numbers for the APM 100/110 Degree series?

 

Notably the :

 

20mm APM 100 deg

13mm APM 100 deg

9mm APM 100 deg

5mm APM 110 deg

3.5mm APM 110 deg

 

Many thanks

 

HB

[f18dad]

Hi Folks, 

 

Anybody have numbers for the APM 100/110 Degree series?

 

Notably the :

 

20mm APM 100 deg - Between A&B. Closer to A

13mm APM 100 deg - Shade past B

9mm APM 100 deg - E

5mm APM 110 deg

3.5mm APM 110 deg

 

Many thanks

 

HB

[Bintang13]

Hi,

 

Can anyone please share their experiences with a Paracorr 2 using a linear binoviewer in a Dob. What setting would be best. Do you use the settings designated for the eyepiece or a setting for all eyepieces. Thanks for your input.

 

Jim

[Starman1]

Hi,

 

Can anyone please share their experiences with a Paracorr 2 using a linear binoviewer in a Dob. What setting would be best. Do you use the settings designated for the eyepiece or a setting for all eyepieces. Thanks for your input.

 

Jim

That binoviewer must use the included 2X Barlow to move the focal plane out far enough to get it to focus in a newtonian.

I doubt that it will work in a PowerMate, but here is how to tell:

--focus one of the eyepieces in the Paracorr after finding the correct setting for that eyepiece.

If you don't know the correct setting for the eyepiece, insert another eyepiece for which you DO know the setting and focus the scope with that eyepiece.

Then, without touching the focuser, insert the eyepiece you plan to use in the binoviewer into the Paracorr and focus it using the tunable top.

--remove the eyepiece and place it in the binoviewer along with its mate.

--without touching the focuser, put the binoviewer + Barlow in the Paracorr (make certain the Barlow doesn't stick out of the bottom of the 1.25" adapter by more than a couple mm).

--focus the binoviewer by turning the tunable top to focus (you'll have to rotate the binoviewer after it's focused, of course).

--if it came to focus, record the setting and use that setting every time you insert the binoviewer with those eyepieces the next time.

--repeat the 'focus with the tunable top' of the Paracorr for all other eyepiece pairs, recording the settings for each.  You will dial the top to those recorded settings every time you use the binoviewer with each pair of eyepieces.

 

If it does not come to focus at setting A, and you need just a little more in focus of the eyepiece, buy or use a 1.25" adapter on the binoviewer that is a lot shorter than the Paracorr adapter.

The Paracorr adapter is 10.5mm tall above the Paracorr, and there are adapters out there of 1mm height (Baader Push-Fix), -1.5mm (Tele Vue In-Travel adapter) and even more (Astrosystems Ultra Low adapter).

After changing the adapter, focus using the tunable top and binoviewer, after setting it correctly with a single eyepiece and no binoviewer, to get it to focus somewhere in the range of the tunable top.

 

If it does not come to focus at setting H, and you need a little more out focus, you can gain 6mm with the Tele Vue Hi-Hat adapter (it's 16.5mm tall) or simply by pulling the binoviewer out of the Paracorr until it's in focus.

(after setting the Paracorr properly with a single eyepiece without the binoviewer).  If you feel that is unsafe, you can add a barrel extender to the Barlow to allow you to safely pull the binoviewer farther out.

 

If that isn't sufficient, either way, you cannot use the binoviewer in the Paracorr.  You might be able to use it without the Paracorr, in that case.

Remember, every pair of eyepieces will take a different setting of the Paracorr unless your different pairs of eyepieces are parfocal.

Edited by Starman1, 03 March 2024 - 05:13 PM.

[Bintang13]

Hi starman 1,

 

Very much appreciate your reply. The linear binoviewers don’t need a barlow to come to focus in a Dob. I don’t think it affects your instructions at all though. Thank you also for the tips regarding the in travel and hi hat adapters. I had studied your instructions some time ago appreciate your confirmation of the method. I’m also concerned about the combined weight of the setup so this might be a very short lived experiment. Thank you very much for taking the time to reply.

 

Jim

[Bintang13]

I wanted to thank you very much for your instructions for using the linear binoviewers with a Paracorr 2. After bringing a single 18.2 Delite to focus on setting D I then inserting the binoviewers, it came to focus at the same point. Once I let it all settle only the very very slightest bit of fine tuning was required. Thank you again for your help.

 

Jim

[BGazing]

Any reason why I should not use this adapter https://www.baader-p...-part-15b).html instead of the supplied Paracorr 2 one? It is 1mm lower, which is close enough, and even better for Delos 17, which actually has setting lower than A as the correct one, and is also threaded for filters. If I understand correctly, there is a ring stop that prevents 2 inch filter hitting the lens anyway.

[Starman1]

Any reason why I should not use this adapter https://www.baader-p...-part-15b).html instead of the supplied Paracorr 2 one? It is 1mm lower, which is close enough, and even better for Delos 17, which actually has setting lower than A as the correct one, and is also threaded for filters. If I understand correctly, there is a ring stop that prevents 2 inch filter hitting the lens anyway.

I see no reason not to use that Baader adapter.  It is not compatible with the 6mm and 8mm Ethos when used as 1.25" eyepieces, and it's too tall to use with a 17.5mm Morpheus, but, other than that,

it should work fine.

Here is another adapter with filter threads that would work fine as well:

https://agenaastro.c...iBoCpsgQAvD_BwE

And another, with filter threads that is even a bit shorter (it's the one on the right):

https://www.astrosys...ieceadapter.htm

Edited by Starman1, 03 April 2024 - 09:32 AM.

[BGazing]

I see no reason not to use that Baader adapter.  It is not compatible with the 6mm and 8mm Ethos when used as 1.25" eyepieces, and it's too tall to use with a 17.5mm Morpheus, but, other than that,

it should work fine.

Here is another adapter with filter threads that would work fine as well:

https://agenaastro.c...iBoCpsgQAvD_BwE

And another, with filter threads that is even a bit shorter (it's the one on the right):

https://www.astrosys...ieceadapter.htm

Actually just dug out (under a ton of astro junk, pardon, equipment) something resembling the second one. Has 2mm more optical path than the stock Paracorr adapter, which means all settings would have to shift one letter to the right. Baader one is 1mm shorter, so good for Delos 17.

Not a bad idea to have a couple of them on hand and play around when filters are needed (13mm and above, basically).

[Starman1]

Actually just dug out (under a ton of astro junk, pardon, equipment) something resembling the second one. Has 2mm more optical path than the stock Paracorr adapter, which means all settings would have to shift one letter to the right. Baader one is 1mm shorter, so good for Delos 17.

Not a bad idea to have a couple of them on hand and play around when filters are needed (13mm and above, basically).

If the adapter is 2mm TALLER than the Paracorr adapter, no eyepiece using setting A will work any more.

And it means all eyepieces will use one setting in from their usual setting with the Paracorr adapter.

If you have eyepieces that need a lower setting than A, what you need is an adapter that has a lower height above the Paracorr than the original adapter.

[BGazing]

If the adapter is 2mm TALLER than the Paracorr adapter, no eyepiece using setting A will work any more.

And it means all eyepieces will use one setting in from their usual setting with the Paracorr adapter.

If you have eyepieces that need a lower setting than A, what you need is an adapter that has a lower height above the Paracorr than the original adapter.

Yes, that is what I have understood. Shorter is okay...taller no-go for A position.

[Bodon]

GDay all

 

My question is related to the Paracorr type 2 but unsure if Im in the right area to post.  But there are definitely some gurus here.  I want to unscrew the top of the Paracorr.  Instructions say to back off the grub screw under flange.  Did that until it came out.  But I cannot unscrew the top.  I just gave it a light turn and no movement.  Are they usually hard to unscrew?  Plenty of pictures on the net but little info taking the top off.  I dont want to bust or scratch my new addition. Appreciate a heads up.  Ta

[Starman1]

I believe removing the setscrew should allow you to unscrew the top.

Check to see if they have added a second setscrew to the recent production.

If not, the top should unscrew from the lower barrel.

[chuckles]

Any idea what the setting would be for the XW 16 and 23 in the Paracorr 2? I may have the chance to try them out tonight but don’t even know where to begin?

[Starman1]

Any idea what the setting would be for the XW 16 and 23 in the Paracorr 2? I may have the chance to try them out tonight but don’t even know where to begin?

Do you have even one other eyepiece that you know the setting for?

 

Then insert that eyepiece and dial in its setting and focus the scope.

Insert the XW 85 and focus it using the tunable top of the Paracorr, not the focuser.

The setting that results is the correct setting for the eyepiece, and you can pre-dial that setting the next time you use the eyepiece.

 

I remember that Pentax said that the focal planes were at the shoulders of the 85° eyepieces, which would imply setting E would be correct,

since E is the focal plane of the Paracorr.  You could verify that by using the technique above.

If you have no other eyepieces to start with, then I would simply start with setting E.

[chuckles]

Thanks! I do have others and will try this if he brings them and report back.

[BGazing]

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.

I've just realized addendum to this rule...one has to make sure to tighten the friction screw on the focuser. I had my FTF screw lose a couple of times and getting an Ethos in our out of it can pull the focus in or out. Undercuts...