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Equipment Discussions >> Eyepieces

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nevy
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Reged: 02/07/12

Loc: UK
Re: List of Paracorr settings for all brands of EP new [Re: nevy]
      #5334547 - 07/25/12 11:30 AM

Quote:

Does anyone know the best setting for a tv 55mm plossl ( smoothside) for the Paracorr type2 ?



No need to answer this question, I tried it last night at f5 and it doesn't need one , it's pretty sharp at the edges ,( at F10 it's superb) ;-/

Edited by nevy (07/25/12 11:35 AM)


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Starman1
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Reged: 06/24/03

Loc: Los Angeles
Re: List of Paracorr settings for all brands of EP new [Re: nevy]
      #5334641 - 07/25/12 12:07 PM

Since that eyepiece produces an 11mm exit pupil in your dob, do you notice the shadow of the secondary? Generally people who have f/5 dobs rarely go longer than about a 31-35mm eyepiece focal length.

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nevy
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Re: List of Paracorr settings for all brands of EP new [Re: Starman1]
      #5334722 - 07/25/12 12:47 PM

Quote:

Since that eyepiece produces an 11mm exit pupil in your dob, do you notice the shadow of the secondary? Generally people who have f/5 dobs rarely go longer than about a 31-35mm eyepiece focal length.



No I didn't , I didn't expect too much from it in the dob as I bought it mainly for the C11 but I was quite surprised at how good it performed in the dob , I like it alot. The only problem I had was that I needed to pull the eyepiece right to the top of the focuser to achieve focus ,so for safety I will put the tv barrel extender on it next time.


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Sarkikos
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Re: List of Paracorr settings for all brands of EP new [Re: nevy]
      #5369644 - 08/15/12 07:57 AM

Last Sunday night I took my family to a dark site for the Perseids. To save room in our vehicle, I brought along my 5" f/5 Dob instead of the 10".

While I was there, I tried my Baader Hyperion Zoom in the Paracorr Type I to determine the best setting. I had attempted the Zoom in 1.25" mode before, but of course there was not enough in focus.

I thought I had attempted 2" mode with my 10" Dob and it had not worked (not enough in focus). But this time I made sure to prime the 5" with a TV Plossl 25mm in the Paracorr, and to change the Zoom to 2" mode.

I discovered that the Baader Zoom would indeed come to focus in 2" mode at setting 1. The stars were nice little points of light from center to edge. They were still in focus - or very nearly so - whether the Zoom was at 24mm or 8mm or anywhere in between. Only a very small tweak of the focuser was needed, if at all, at 8mm vs 24mm.

The next time I take my 10" Dob to the dark site I'll retest the Zoom in 2" mode in my Paracorr, being sure to prime it first with the TV Plossl. I'm pleased that the Baader Zoom works well in the Paracorr, since that is the eyepiece that sees the most sky time in my Dobs.

Mike


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Sarkikos
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Re: List of Paracorr settings for all brands of EP new [Re: Sarkikos]
      #5369670 - 08/15/12 08:22 AM

Recent updates for eyepiece settings in Paracorr Type 1 - the good, the bad and the ugly!

Baader BGO 9mm: not enough in focus
Sky Watcher Super Plossl 9mm: not enough in focus
Edmund RKE 12mm: Setting 4.75
Baader BGO 12.5mm: not enough in focus
Brandon 16mm: Setting 4
Baader BGO 18mm: not enough in focus
Surplus Shed WF Kellner 19.9mm: Setting 2.5 (for what it's worth )
LOMO Ortho 20mm (12.5x microscope EP): Setting 4.5
Russel RK 20mm: not enough in focus
Faworski Super Abbe Ortho 24mm: Setting 3.75
Sterling Plossl 25.1mm: not enough in focus
Baader Mark-II Zoom (2" mode only): Setting 1 (for all focal lengths)
ES 82deg 30mm: Setting 1.5
Orion Ultrascopic 35mm: not enough in focus
Vixen Ortho 40mm: Setting 3.5

Mike


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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: List of Paracorr settings for all brands of EP new [Re: Sarkikos]
      #5369914 - 08/15/12 11:14 AM

Mike,
Since most of these are 1.25" eyepieces, what you need for the ones that require more infocus is an adapter that allows the eyepiece to move substantially closer to the Paracorr's lens.
Here is what you need:
http://www.astrosystems.biz/eyepieceadapter.htm
For a lot of eyepieces, it's worth its weight in gold.


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Sarkikos
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Re: List of Paracorr settings for all brands of EP new [Re: Starman1]
      #5380695 - 08/22/12 09:20 AM

Yes, thanks, Don. I already purchased one of those awhile back. In fact, I think it may have been you that gave me the advice at that time!

The only downside to the adapter is that you need to use a little hex key to secure or remove the eyepiece. I guess I could buy multiple adapters for all my 1.25" eyepieces that won't come to focus any other way in the Paracorr. But that would cost some serious money for me.


Mike


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Sarkikos
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Re: List of Paracorr settings for all brands of EP new [Re: Sarkikos]
      #5380703 - 08/22/12 09:26 AM

Update on the Baader Hyperion Zoom: It will also work in my 10" f/4.8 Dob with Paracorr Type 1 Setting 1, as it did in my 5" f/5 Dob. (I primed the Paracorr with my TV Plossl 25mm.) That is what I expected. The particular Newt that the Paracorr is in should not matter.

However, the Baader Zoom must be in 2" mode in order to come to focus.

Mike


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Starman1
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Reged: 06/24/03

Loc: Los Angeles
Re: List of Paracorr settings for all brands of EP new [Re: Sarkikos]
      #5380822 - 08/22/12 10:37 AM

Quote:

Yes, thanks, Don. I already purchased one of those awhile back. In fact, I think it may have been you that gave me the advice at that time!

The only downside to the adapter is that you need to use a little hex key to secure or remove the eyepiece. I guess I could buy multiple adapters for all my 1.25" eyepieces that won't come to focus any other way in the Paracorr. But that would cost some serious money for me.


Mike



Adjust the small setscrew in the adapter so the fit of the eyepiece is tight enough you have to "rotate it in" and "rotate it out". Then, every 1.25" eyepiece can be placed in and removed from the adapter without having to snug down the setscrew on each one.


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Sarkikos
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Re: List of Paracorr settings for all brands of EP new [Re: Starman1]
      #5380887 - 08/22/12 11:09 AM

Thanks, I'll try that.

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Busguy
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Reged: 06/14/07

Loc: Kentucky
Re: List of Paracorr settings for all brands of EP new [Re: Sarkikos]
      #5381069 - 08/22/12 01:12 PM

Anyone input the Delos line into the settings?

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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: List of Paracorr settings for all brands of EP new [Re: Busguy]
      #5381374 - 08/22/12 04:31 PM

Quote:

Anyone input the Delos line into the settings?



All the Delos eyepieces except the 17.3 and 14 will use setting "D" with the Paracorr's supplied 1.25" adapter.
The 17.3 and 14 will require setting "A" for right now, also using the 1.25" adapter.
There may be another, lower-profile, 1.25" adapter for the 17.3 and 14.0 a little later on, as the "perfect" correction for those two will require a setting a little farther in than setting "A".
But "A" will still correct a lot better than no Paracorr, in the same way that the original Paracorr didn't completely correct the 31 Nagler or 21 Ethos but they still were improved a lot over no Paracorr.


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miguel gonzalez
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Loc: Cadiz - Spain
Re: List of Paracorr settings for all brands of EP new [Re: Starman1]
      #5423266 - 09/16/12 04:31 AM

Hi all..

I have TV paracorr type 1.

And I have Docter/Zeiss 12.5mm UWA and Nikon Nav Sw 10 mm eyepieces.
What settings should I use in the Paracorr?

Thanks

Edited by miguel gonzalez (09/16/12 12:03 PM)


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Starman1
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Reged: 06/24/03

Loc: Los Angeles
Re: List of Paracorr settings for all brands of EP new [Re: miguel gonzalez]
      #5423862 - 09/16/12 02:28 PM

Let's review how to set the Paracorr when you don't know the correct setting and you have no TeleVue eyepieces (if you have a TeleVue eyepiece, use their prescribed setting for that eyepiece and all the other eyepieces will follow--instructions follow:)

Start with the out-most setting of the Paracorr. Focus the telescope and examine the edge of field stars. Still see coma? Move the Paracorr in one setting and refocus. Still see coma, but it's improved? Continue in one more setting.
With trial and error, you will find one setting that produces the least coma at the edge of the field. If aberrations are not fully corrected, it's likely the eyepiece has some residual astigmatism at the edge of the field that the Paracorr won't correct.

Once you have the proper setting for that eyepiece, write it down so you can return the Paracorr to that setting before using that eyepiece the next time.

Now, how to set the other eyepieces once you have a perfect setting for that one eyepiece:
Put the second eyepiece in and focus using the tunable top of the Paracorr. When that eyepiece is in focus, look at the tunable top setting. That will be the setting for that eyepiece. Write it down so you can go to that setting before the next use of that eyepiece.

In that manner, you can do an entire collection of eyepieces without knowing in advance what the settings for those eyepieces are.

As you can see, the tunable top makes all your eyepieces parfocal--only the movement in and out of the tunable top before you insert the next eyepiece is required, plus, perhaps, a tiny bit of refocusing. But the movement of the focuser will be tiny as long as the Paracorr is used.

What if you cannot correct the coma of an eyepiece because the Paracorr's settings don't extend far enough to fully correct that eyepiece?
Well, that's not unusual. The 31 Nagler and 21 Ethos were in that category on the original Paracorr. And the 17.3 and 14 Delos are in that category on the Paracorr II.
Don't worry about it. If the eyepiece is close to the ideal coma correction setting the images will still be improved significantly over no Paracorr at all.
BUT, don't use that eyepiece to determine the settings for your collection. Use an eyepiece that has its best coma correction among the settings of the Paracorr. And, to make sure you have a good starting point, use your eyepiece that has the widest apparent field of view because coma will be more visible in that eyepiece than in narrower field eyepieces.

After you have determined the correct settings for all your eyepieces, even those whose correction is not ideal at one extreme or the other of the Paracorr settings, hopefully you will have written down the settings. If, like me, you don't want to resort to a list before inserting the eyepiece, use a label maker to put the Paracorr setting on the side of the eyepiece so you don't have to remember.

There is an alternative to this, and I admit to using it when I'm using an eyepiece briefly and then inserting another eyepiece: Having the setting absolutely perfect for one eyepiece, I insert another and simply focus using the tunable top. Then, I touch up the focus a tad with the main focuser. That way, I don't even have to read the label on the eyepiece to find the correct setting for the next eyepiece. It helps if you have eyepieces that all use extreme settings (most of mine use one extreme or the other) and your less-often-used eyepieces use an intermediate setting.

So, as you can see, the purpose for this thread is a little unnecessary. All you need to do is take the time to get one eyepiece dialed in and all the rest follow.

Edited by Starman1 (09/16/12 02:31 PM)


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miguel gonzalez
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Reged: 10/08/05

Loc: Cadiz - Spain
Re: List of Paracorr settings for all brands of EP new [Re: Starman1]
      #5423942 - 09/16/12 03:24 PM

Thank you very much, Don.

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Michael11
sage


Reged: 06/24/06

Loc: Israel
Re: List of Paracorr settings for all brands of EP new [Re: miguel gonzalez]
      #5425364 - 09/17/12 12:42 PM Attachment (89 downloads)

Hello,
I'm using a combination of a universal paracorr (plu-1106) and a tunable top (see attachment). Should I follow the same settings as with type-1 visual?

Another question - can I simply make the distance between eyepiece field lens and the paracorr lens equal to 55mm, or there are other considerations?

thanks in advance.


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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: List of Paracorr settings for all brands of EP new [Re: Michael11]
      #5425584 - 09/17/12 02:38 PM

Quote:

Hello,
I'm using a combination of a universal paracorr (plu-1106) and a tunable top (see attachment). Should I follow the same settings as with type-1 visual?

Another question - can I simply make the distance between eyepiece field lens and the paracorr lens equal to 55mm, or there are other considerations?

thanks in advance.



When the tunable top is added, you essentially have a Paracorr I, so settings will be the same.
The 55mm spacing is between the lens of the Paracorr and the Focal Plane of the eyepiece. That focal plane can be anywhere in the barrel:
in simple eyepieces it's where the iris (knife-edge baffle) is below the bottom lens of the eyepiece. In complex eyepiece designs it can be in-between lenses.

But, as I mentioned, you only have to get one eyepiece right and you can determine the setting for all the others visually and without measurements.


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Michael11
sage


Reged: 06/24/06

Loc: Israel
Re: List of Paracorr settings for all brands of EP new [Re: Starman1]
      #5427437 - 09/18/12 01:35 PM

Ok, thanks.

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csrlice12
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Re: List of Paracorr settings for all brands of EP new [Re: Michael11]
      #5465269 - 10/11/12 12:05 PM

Looking at the Televue site, the 13mmT1 (nor any other T1s) are listed. Any ideas why not?

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Starman1
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Reged: 06/24/03

Loc: Los Angeles
Re: List of Paracorr settings for all brands of EP new [Re: csrlice12]
      #5465356 - 10/11/12 01:08 PM

Quote:

Looking at the Televue site, the 13mmT1 (nor any other T1s) are listed. Any ideas why not?



Maybe because they haven't been made since the '80s--since before there was a Paracorr?
It would be easy enough to determine the correct setting, though, using the same technique one uses on a non-TeleVue eyepiece (see previous posts).


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