Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

8" SCT for a grab and go setup

  • Please log in to reply
51 replies to this topic

#26 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 05 December 2019 - 08:06 AM

Every one has a different definition of grab and go. For me it is a single trip to a car (mount one hand, OTA bag in another, and a backpack with all the other stuff) and setup time of ~10 minutes. 

 

I live in a warm country, can store the telescope outside, and don't care to wait ~30 minutes for initial cool down. I don't expect to do planetary sessions at 400X right away. Just want a telescope which requires no physical effort to setup. And I sketch deep sky objects so tracking is a requirement

 

Anyway already ordered it - 799$ at latest sale so wish me luck tongue2.gif .


  • jimandlaura26, Delta608 and cupton like this

#27 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 06 December 2019 - 05:24 AM

Any knows exact size and type of collimation screws for 8SE secondary mirror? I'd like to order allen screws before the telescope arrives ...



#28 Tfer

Tfer

    Vostok 1

  • -----
  • Posts: 182
  • Joined: 05 Sep 2019
  • Loc: Northern Alberta, Canada

Posted 09 December 2019 - 02:41 AM

My grab and go, is a 6” Nextstar SE.  It stays on its mount, and I can carry it out to my back deck in a single trip. The winter months here get COLD; below -30C isn’t unusual, and when clear skies are going to present themselves, I want to be quick.

 

my routine involves checking my StarCaster app, and if it looks acceptable, I run the scope outside before the sun sets, allowing it to equalize.  Then if the skies act as predicted, bundle up, and head outside with a couple of eyepieces.

 

i can usually handle 20-30 minutes before needing to warm up.

 

Goto ability is wonderful under these circumstances.  My 10” Dob is for the other 6 months of the year, when I can leisurely wander the sky. 


  • Ssayer likes this

#29 Bataleon

Bataleon

    Ranger 4

  • *****
  • Posts: 381
  • Joined: 29 Aug 2019

Posted 09 December 2019 - 02:44 AM

Any knows exact size and type of collimation screws for 8SE secondary mirror? I'd like to order allen screws before the telescope arrives ...

They're standard Phillips head screws... Or am I misunderstanding? Are you looking to change them to Allen heads? 8519fa638ac7b3cdfc24df0b1ef056da.jpg

Sent from my SM-N960F using Tapatalk
  • Rick-T137 likes this

#30 Bill Barlow

Bill Barlow

    Aurora

  • *****
  • Posts: 4,709
  • Joined: 03 Dec 2007
  • Loc: Overland Park KS

Posted 09 December 2019 - 11:04 AM

These Phillips screws for adjusting the secondary mirror are very soft and the heads can strip.  I have done this myself on a few occasions.  So when I got a C11 I removed these and replaced them with Allen head screws.  Much easier to adjust and much harder metal.

 

Bill


  • Rick-T137 likes this

#31 NMBob

NMBob

    Surveyor 1

  • *****
  • Posts: 1,606
  • Joined: 21 Nov 2015
  • Loc: New Mexico

Posted 09 December 2019 - 04:48 PM

For some reason my Edge8 got WAY out of alignment on Saturday during an outreach thing. Good thing it was cloudy and the nearby mountain had an "M" lit up at the peak with light bulbs. What a pain in the neck it was with the stock screws like Bataleon's. It's going to get the Edge11 treatment with Bob's Knobs. I never want to go through that back and forth with a screwdriver junk again. Never have had to with any C-something. No idea why it all-of-a-sudden got so out of whack. I've barely had to touch it in the last two years. Maybe the Loctite finally let loose (see the link). Sure worked well once I got it straightened out. :)

 

https://www.passcal....e/20181106.html

 

Bob



#32 coopman

coopman

    Fly Me to the Moon

  • *****
  • Posts: 6,502
  • Joined: 23 Apr 2006
  • Loc: South Louisiana

Posted 09 December 2019 - 07:20 PM

Back before the reflectix insulation solution, I tried to make a C8 my grab & go rig.  I observe in my yard, so I don't have to go very far.  I found out real quick that I had better take a refractor out there to use while my C8 was acclimating to the outside temperature.  I use an insulated Evolution C8HD now and it seems to be a good solution for my current needs.  It is also my first go-to scope and go-to is the greatest thing since sliced bread!      


  • eros312, Bean614 and NMBob like this

#33 stevew

stevew

    Now I've done it

  • *****
  • Posts: 6,522
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 10 December 2019 - 02:51 AM

As was said before, grab and go means different things to different people.

To some it means a one handed, out the door rig, to others it's just something simpler than a GEM, with batteries, and hand controllers.

Here is my C8 on a W.O. EZ Touch. It's a great rig, that moves very smoothly without the weight of a traditional C8 mount.



#34 stevew

stevew

    Now I've done it

  • *****
  • Posts: 6,522
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 10 December 2019 - 02:51 AM

As was said before, grab and go means different things to different people.

To some it means a one handed, out the door rig, to others it's just something simpler than a GEM, with batteries, and hand controllers.

Here is my C8 on a W.O. EZ Touch. It's a great rig, that moves very smoothly without the weight of a traditional C8 mount.

Attached Thumbnails

  • 20190701_211159_resized.jpg

  • Delta608, Paul Morow, Rick-T137 and 2 others like this

#35 stevew

stevew

    Now I've done it

  • *****
  • Posts: 6,522
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 10 December 2019 - 02:56 AM

My C5....

Attached Thumbnails

  • C5.jpg

  • Rick-T137 and Stevegeo like this

#36 Bill Barlow

Bill Barlow

    Aurora

  • *****
  • Posts: 4,709
  • Joined: 03 Dec 2007
  • Loc: Overland Park KS

Posted 10 December 2019 - 09:24 PM

As was said before, grab and go means different things to different people.

To some it means a one handed, out the door rig, to others it's just something simpler than a GEM, with batteries, and hand controllers.

Here is my C8 on a W.O. EZ Touch. It's a great rig, that moves very smoothly without the weight of a traditional C8 mount.

Steve, what tripod are you using with the EZ Touch altaz mount?  Looks pretty sturdy and stable.  Thanks.

 

Bill



#37 stevew

stevew

    Now I've done it

  • *****
  • Posts: 6,522
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 10 December 2019 - 09:31 PM

It's an Oberwerk.

https://oberwerk.com...m-oberwerk-usa/



#38 Delta608

Delta608

    Viking 1

  • *****
  • Posts: 792
  • Joined: 19 May 2008
  • Loc: Tampa Bay Florida

Posted 11 December 2019 - 08:31 AM

As was said before, grab and go means different things to different people.

To some it means a one handed, out the door rig, to others it's just something simpler than a GEM, with batteries, and hand controllers.

Here is my C8 on a W.O. EZ Touch. It's a great rig, that moves very smoothly without the weight of a traditional C8 mount.

 

  Do you think that a Meade Tripod made for a LX200 would work under the EZ Touch...??   You gave me some ideas..(De-forked LX200 8")



#39 stevew

stevew

    Now I've done it

  • *****
  • Posts: 6,522
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 11 December 2019 - 09:11 PM

I'm sure you could find a way to make it work,

I think the EZ Touch uses a 3/8 center bolt or whatever the metric equivalent is.


  • Delta608 likes this

#40 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 15 December 2019 - 05:52 PM

Well, the 8SE arrived. All appears well, except that I can see some ~ 1 inch spot on the side of the corrector. It shows only under a strong illumination by a flashlight from a certain angle (1st photo). Can't see it when just looking through the corrector (2nd photo). Will it affect my views or its negligible?

Attached Thumbnails

  • spot 1.jpg
  • spot 2.jpg

Edited by Michael11, 15 December 2019 - 05:53 PM.


#41 Bill Barlow

Bill Barlow

    Aurora

  • *****
  • Posts: 4,709
  • Joined: 03 Dec 2007
  • Loc: Overland Park KS

Posted 15 December 2019 - 08:29 PM

No, it shouldn't make any difference I would think since it appears transparent when looking straight at the corrector lens.  It's not a reflection of some kind when the light hits it in at certain angle?  

 

Bill 



#42 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 16 December 2019 - 12:30 AM

It's not a reflection of some kind when the light hits it in at certain angle?

It's not a reflection. I think it's something which formed during coating process (maybe a spot by which corrector was held in place), or just some mark on inner surface. 


Edited by Michael11, 16 December 2019 - 12:31 AM.


#43 stevew

stevew

    Now I've done it

  • *****
  • Posts: 6,522
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 16 December 2019 - 02:26 AM

A fingerprint maybe?

If it were mine, I would test the scope to see how it performs. If it's got good correction showing smooth diffraction rings on either side of focus I wouldn't worry about it.

When I purchased my 16 inch Starfinder in the early 90s it was missing a small spot of aluminum where the cork on one of the mirror clips had rubbed it off.

The mirror tested well, so I kept it, and it's been a great performer for many years.



#44 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 07 January 2020 - 03:44 AM

Anyway so far I'm enjoying it. Takes a single trip to a car and ~15 minutes to setup and align. I guess it will be faster when I get more familiar with the scope.

 

I'm storing the OTA mounted on the fork, in original shipping foam cut to fit a 28" suitcase. Hope it's OK to store it like that in "standing" position.

 

The mount is indeed shaky, but these celestron vibration suppression pads actually do work - they decreased damping time from 5 to 1.5 seconds, which is completely manageable.

 

GOTO is really accurate, far better than what I get from my AZ-EQ6 in "az" mode. I'm using 2 star alignment. 

 

Somehow there is no image shift at all while focusing (at 200x). Though the focuser knob sometimes slightly "slips" during cold weather when changing direction (which is better than having image shift I guess). Maybe I'll consider that chinese 1:10 reduction knob which is sold for 100$ if the future...

 

I currently work with 3 eyepieces - 10, 18 and 28 mm (82°). I still haven't really got hang of the collimation, so I'm not going for higher powers...

 

As advised in some threads I've read here - I'm using a TalentCell Rechargeable 11000mAh battery, and also keep AA rechargeables in the battery tray for backup.

 

And of course I replaced that horrible finder with a Telrad :-)

Attached Thumbnails

  • 8se-case-s.jpg
  • 8se-setup-s.jpg

Edited by Michael11, 07 January 2020 - 04:06 AM.

  • eros312, Astrojedi, mr_snout and 3 others like this

#45 mr_snout

mr_snout

    Mariner 2

  • -----
  • Posts: 217
  • Joined: 10 Jan 2017
  • Loc: San Antonio Texas

Posted 08 January 2020 - 01:02 AM

As was said before, grab and go means different things to different people.
To some it means a one handed, out the door rig, to others it's just something simpler than a GEM, with batteries, and hand controllers.
Here is my C8 on a W.O. EZ Touch. It's a great rig, that moves very smoothly without the weight of a traditional C8 mount.


Agreed. If u just want a good view of the moon real quick, the planets and some obvious Messier objects, then a Mak 90-127 is what I consider a grab and go. The C6 is noticeably more bulky and heavier than my SW 127. It just is for a few minutes of observing.

#46 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 10 January 2020 - 04:28 AM

I'm slightly confused with the collimation: One of the screws has to be snug all the way in, and the opposite has to be slightly lose in order to achieve collimation. Is that normal? I think this way the scope won't hold collimation too well. Is there a way to fix it? Maybe add a raiser or a spring in the middle of the secondary holder? 


Edited by Michael11, 10 January 2020 - 04:28 AM.


#47 whizbang

whizbang

    Viking 1

  • *****
  • Posts: 859
  • Joined: 18 Mar 2018
  • Loc: NE of Seattle, WA

Posted 12 January 2020 - 02:20 PM

No.  It's not normal.  All three screws should be snug, and, appear about the same depth.  Also, all my SCT's usually have held collimation for well over a year.

 

If that is a new scope, you should contact the service dept for help and/or consider returning it under warranty.



#48 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 13 January 2020 - 06:43 AM

Easier said than done - I ordered it from abroad.



#49 charlesgeiger

charlesgeiger

    Messenger

  • -----
  • Posts: 471
  • Joined: 12 Dec 2011

Posted 17 January 2020 - 08:02 PM

I would start over with the collimation.  Do remember you cannot unscrew all the 3 secondary screws at one time or you will drop your secondary into the optical tube with devastating results.  So start with the screws loosened but not too loose.  Allign the corrector shadows from the front of the telescope making sure the circles are all concentric.  Then do a star collimation noting that you need the 'star' always returned to the center of your field of view for further adjustment.  The final collimated star should be in the exact center of the field with concentric circles around the shadow of the secondary on both sides of focus.  Again you need to finish this process up with a high power eyepiece on a good night with steady seeing.  If you have a reticle eyepiece use it such as a 12.5 mm.

If you cannot get rid of the very unbalanced depth of the adjustment screws in this process look further...Is your corrector correctly installed flat against the gasket/housing?  Is your secondary centered in the corrector?  Is the primary mirror and baffle centered in the telescope body?

If you have a fastar secondary, make sure it is indexed properly in the secondary cell.

Some thoughts to try and eliminate any source of error in the placement of the primary, secondary, and corrector.  Also, make sure the nut or baffle tube is snug up to the main mirror to eliminate the possibility the mirror is tipping on the baffle.

Charlie



#50 Michael11

Michael11

    Messenger

  • *****
  • topic starter
  • Posts: 461
  • Joined: 24 Jun 2006
  • Loc: Israel

Posted 18 January 2020 - 05:18 PM

Thanks, I'll check that everything is centered. And I'll recollimate when my allen screws set arrives

 

If you have a fastar secondary, make sure it is indexed properly in the secondary cell.
 

Yes its a fastar secondary. What do you mean by that?

 

Anyway If I won't find the solution - think I might add a central spring (or 3 springs for each screw) and use slightly longer screws - this should allow easier and more accurate collimation.

 

Also, make sure the nut or baffle tube is snug up to the main mirror to eliminate the possibility the mirror is tipping on the baffle.

Does it require disassembly? Anyway there is almost zero image shift even at high powers, so I don't think it's the issue.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics