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Advice on possible improvments to my XT8 Classic?

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#1 James1996

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Posted 03 March 2021 - 04:31 PM

So since I've decided to stick with my XT8 Classic as my primary scope for the foreseeable future. I've been thinking about possible things I can do to improve it like a better focuser and/or a lighter weight rocker box. Anyone got any opinions on this guys (http://dobstuff.com/...omrockerbox.htm) replacement rocker box's? His stuff on his website looks good. I'd try my hand at building a better rocker box my self but I simply don't have the tools for that. Any opinions on possible focuser upgrade options? The XT8 Classic's stock focuser isn't terrible by any means it's way better then that cheap plastic crap Orion puts on the XT4.5 & XT6 but it's not as good as my new AT80ED's dual speed R&P focuser. I think I'd like a new focuser of comparable quality to my AT80ED's focuser. Any suggestions? I likely wont be making these possible upgrades to the XT8 anytime soon this is just me thinking about thing's I can do to improve my current main scope sometime in the future. thinking1.gif 



#2 Mike G.

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Posted 03 March 2021 - 04:38 PM

I have a Dobstuff base on my 12" Lightbridge - it's great!  I bought the self-assemble kit but had him add one inch to the scope height so the stupid Meade fan connector would stop hitting the tension knob in the center of the base.  I also added a GSO Crayford 2 speed focuser that is wonderful as well.  easy peasy, fit right into the existing holes, no drilling or cussing.  also made a bigger EP tray since I typically have 4 - 2" EPs in use.


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#3 ayryq

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Posted 03 March 2021 - 05:40 PM

I've been thinking about an equatorial mount for my xt8-plus. Maybe something to think about combining with the rocker box upgrade. It's the opposite of "lighter" though.

 

Have you already put a fan on the back? Better collimation knobs? Finder upgrades (RACI, telrad?) Do you have a solar filter?


Edited by ayryq, 03 March 2021 - 05:41 PM.


#4 MellonLake

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Posted 03 March 2021 - 06:51 PM

Dob upgrades that really help in my opinion are (in order of importance):

 

1) Gas to dark skies.  Best accessory of all!!!

2) Telrad and/or Laser Finder (read up on laser safety and regulations before buying a laser)

3) High quality collimation tools  (Farpoint laser and Cheshire). 

4) Bob's knobs for the secondary

5) Parallizer for ensuring 1.25" eyepieces and tools are registered correctly in the focuser. 

6) Fan and baffle on the back to cool the mirror.

7) UHC Filter

8) Eyepiece dew heater

9) Flocking the tube to reduce stray light (may need to move the trunnions to get the balance right again)

10) 2 Speed focuser (I have an Orion that I picked up used and very happy with it)

 

I upgraded to the 2 speed focuser but it would not be among my highest priorities. 

 

Hope this helps

 

Rob  


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#5 shohin

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Posted 03 March 2021 - 07:00 PM

I also have an XT8 Classic and looked into upgrading the focuser a while ago.

 

I believe these focusers are direct replacements for the stock focuser.

https://www.telescop...60/p/102075.uts

https://agenaastro.c...dual-speed.html

 

The 2-speed XT8 Plus focuser might also fit if you can find one on the used market.

 

Or you could upgrade your current focuser.

https://www.teleskop...d-focusers.html


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#6 gwlee

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Posted 03 March 2021 - 11:19 PM

So since I've decided to stick with my XT8 Classic as my primary scope for the foreseeable future. I've been thinking about possible things I can do to improve it like a better focuser and/or a lighter weight rocker box. Anyone got any opinions on this guys (http://dobstuff.com/...omrockerbox.htm) replacement rocker box's?

I also have an XT8 Classic. Its original, factory, particle board base weighs 21#. I you want a lighter base, a key question is what does the DobSuff base actually weigh? 

 

A few years ago, I asked the DobStuff owner this question, and he couldn't tell me. He also couldn’t tell me how much the factory XT8  base weighs, which made me question his claim that the DS base is lighter. Hopefully, he can answer these questions today. 


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#7 sevenofnine

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Posted 03 March 2021 - 11:36 PM

The most meaningful upgrade I did to my XT-8 Plus was add a fan. It really makes a difference. I start it about 30 minutes before and leave it on during my sessions. Better eyepieces make a huge difference over plossls in this scope. A good 2 inch wide angle "finder" eyepiece (ES 28/68) and a Baader Mark lV 8-24 zoom with it's 2.25x barlow are all I ever use with this scope. waytogo.gif

Permanent expensive changes to an inexpensive 8 inch Dob? scratchhead2.gif Not sure about that...Good luck!


Edited by sevenofnine, 04 March 2021 - 11:59 AM.

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#8 scotsman328i

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Posted 04 March 2021 - 08:41 AM

Dob upgrades that really help in my opinion are (in order of importance):

 

1) Gas to dark skies.  Best accessory of all!!!

2) Telrad and/or Laser Finder (read up on laser safety and regulations before buying a laser)

3) High quality collimation tools  (Farpoint laser and Cheshire). 

4) Bob's knobs for the secondary

5) Parallizer for ensuring 1.25" eyepieces and tools are registered correctly in the focuser. 

6) Fan and baffle on the back to cool the mirror.

7) UHC Filter

8) Eyepiece dew heater

9) Flocking the tube to reduce stray light (may need to move the trunnions to get the balance right again)

10) 2 Speed focuser (I have an Orion that I picked up used and very happy with it)

 

I upgraded to the 2 speed focuser but it would not be among my highest priorities. 

 

Hope this helps

 

Rob  

Tell you what, Rob? I need to invest in eyepiece dew heaters living down here in Charleston, SC. The humidity plus always a fast dropping dew point. Really is a must!


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#9 Mike G.

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Posted 04 March 2021 - 08:53 AM

the Dobstuff base knocked almost 20 lbs. off the weight of my original particle board base.  it has a smaller footprint (goes through doors easier, fits in the back of the car better) and is considerably stronger at the joints than the particle board.  I'm quite sure there will be significant weight savings, even if he can't tell you exactly what that will be.  even if it was a tossup, it would still be worth it for the smaller footprint and use of actual wood.

 

looking at the previous posts, flocking is cheap and you can do yourself with quite noticeable improvements, Bob's knobs for sure, a rear fan and closing in the rear cell so you get all the benefit of the fan, secondary heater if you live somewhere that dew is a problem and good collimation tools.  finally, at least one very good 2" widefield EP - you deserve it and your scope deserve it.



#10 James1996

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Posted 04 March 2021 - 09:48 AM

Hmm I think I'll buy this https://agenaastro.c...dual-speed.html and this https://agenaastro.c...mage-finder.htm. On second thought I can live with the current rocker box, the XT8 is already light enough I can comfortably carry it around my yard fully assembled. These possible upgrades for the XT8 might come later sometime this year. I'll first be buying a mount & diagonal for my AT80ED as well as new eyepieces for my scopes later this month.


Edited by James1996, 04 March 2021 - 09:59 AM.

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#11 gwlee

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Posted 04 March 2021 - 10:32 AM

the Dobstuff base knocked almost 20 lbs. off the weight of my original particle board base.  it has a smaller footprint (goes through doors easier, fits in the back of the car better) and is considerably stronger at the joints than the particle board.  I'm quite sure there will be significant weight savings, even if he can't tell you exactly what that will be.  even if it was a tossup, it would still be worth it for the smaller footprint and use of actual wood.

 

looking at the previous posts, flocking is cheap and you can do yourself with quite noticeable improvements, Bob's knobs for sure, a rear fan and closing in the rear cell so you get all the benefit of the fan, secondary heater if you live somewhere that dew is a problem and good collimation tools.  finally, at least one very good 2" widefield EP - you deserve it and your scope deserve it.

What scope do you have, what is the weight of the stock base, and what’s the weight of the DS base?


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#12 Mike G.

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Posted 04 March 2021 - 10:43 AM

What scope do you have, what is the weight of the stock base, and what’s the weight of the DS base?

12" Meade Lightbridge.  Dobstuff makes a direct replacement for them as they are pretty popular.  the stock base weighed in at about 38 lbs, the Dobstuff base at about 19 and some change.  but mine had just a bit extra wood since I asked for some added height.  the stock base was huge and a PITA to move around.  the Dobstuff base is a dream.  I actually sent them photos of the completed base which I believe he posted in the blog on his FB page.  I don't have FB so I can't tell you if it's there or not.



#13 ayryq

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Posted 04 March 2021 - 10:51 AM

Hmm I think I'll buy this https://agenaastro.c...dual-speed.html and this https://agenaastro.c...mage-finder.htm. On second thought I can live with the current rocker box, the XT8 is already light enough I can comfortably carry it around my yard fully assembled. These possible upgrades for the XT8 might come later sometime this year. I'll first be buying a mount & diagonal for my AT80ED as well as new eyepieces for my scopes later this month.

The focuser: You MAY want to consider whether the right move is to get a "low-profile" focuser like the ones shohin posted - they may be needed if you decide to get a binoviewer or hook up a camera. I can't answer this myself.

 

The finder: I found that after upgrading to a right-angle finder, I couldn't find anything. The one advantage of the contortions involved with a straight finder is that you're looking up at the sky and can roughly align the scope pretty well. With a RACI finder, I struggled to get even in the ballpark. The solution is to add a 1x finder (Telrad, Rigel, red-dot). This gives you the best of both worlds: Red dot gets you pretty (very) close, then you can use the RACI comfortably. I picked Rigel Quickfinder for my XT8-plus because there didn't seem to be room for a Telrad.


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#14 gwlee

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Posted 04 March 2021 - 11:25 AM

Hmm I think I'll buy this https://agenaastro.c...dual-speed.html and this https://agenaastro.c...mage-finder.htm. On second thought I can live with the current rocker box, the XT8 is already light enough I can comfortably carry it around my yard fully assembled. These possible upgrades for the XT8 might come later sometime this year. I'll first be buying a mount & diagonal for my AT80ED as well as new eyepieces for my scopes later this month.

To me, the biggest benefit of a two speed focuser on the XT8 is that it cuts down on the shakiness the XT8 exhibits while focusing. Keep in mind though that the new focuser will probably be heavier than the stock focuser, which will require adding an equal amount of weight to the mirror end of the scope to counter balance the added weight of the new focuser, increasing the total weight of your XT8. In stock form, the XT8 tends to be nose heavy with anything heavier than the 25mm Plossl and EZFinder that comes with it.

 

You can use lead fishing weights placed near the focuser to simulate the increased weight of the new focuser and additional weights placed underneath the mirror to determine how much weight is required to counter balance the weight of the focuser. Then you can use the temporarily heavier scope for a few days to see whether the additional weight is significant for you at your observing site. 

 

However, if you NEED a cooling fan, the weight of the cooling fan will help to counter balance the weight of a heavier focuser, heavier EPs, and heavier finders. In my climate, I find little benefit from a cooling fan on my XT8. To determine whether you will benefit from installing a cooling fan, you can experiment with a small external fan blowing air onto the primary before going to the trouble and expense of installing a fan that will definitely increase the weight of your scope. 
 

To test the conventional wisdom that a Baltic Birch base always lightens an XT8, I asked CN member, Ken Fiscus, to build  a line-for-line copy of the stock factory base in Baltic Birch for me to test, and it weighs 21#, exactly the same as the stock factory particle board base, and it performs exactly like the stock base. However, I think it looks better, expect it to tolerate the elements better than the factory base, and think it’s a better starting point for some experimental modifications that I want to make to the base. 


Edited by gwlee, 04 March 2021 - 12:20 PM.


#15 gwlee

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Posted 04 March 2021 - 11:31 AM

12" Meade Lightbridge.  Dobstuff makes a direct replacement for them as they are pretty popular.  the stock base weighed in at about 38 lbs, the Dobstuff base at about 19 and some change.  but mine had just a bit extra wood since I asked for some added height.  the stock base was huge and a PITA to move around.  the Dobstuff base is a dream.  I actually sent them photos of the completed base which I believe he posted in the blog on his FB page.  I don't have FB so I can't tell you if it's there or not.

That’s a significant weigh savings. How does the DS base compare to the stock base in regard to stability and freedom from the shakes while focusing?



#16 Mike G.

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Posted 04 March 2021 - 11:47 AM

That’s a significant weigh savings. How does the DS base compare to the stock base in regard to stability and freedom from the shakes while focusing?

truthfully, it seems stable BUT... it does shake some because I use it on my wood deck.  so any walking around makes the deck vibrate, which transfers to the scope.  I rarely take the dob anywhere but when I have, and let others use it, they always comment on how nice the movements are.  I have some anti-vibration pads to put under it but it hasn't been outside lately due to clouds and cold.  hopefully this spring it will get some use.  stability is very good, although as stated, it has a bit extra height and I had to add a tube stop to keep the OTA from dropping unexpectedly which Dobs do at times.  but it did that with the old base as well.

before:

IMG 1760

 

after:

IMG 4107

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#17 gwlee

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Posted 04 March 2021 - 12:14 PM

truthfully, it seems stable BUT... it does shake some because I use it on my wood deck.  so any walking around makes the deck vibrate, which transfers to the scope.  I rarely take the dob anywhere but when I have, and let others use it, they always comment on how nice the movements are.  I have some anti-vibration pads to put under it but it hasn't been outside lately due to clouds and cold.  hopefully this spring it will get some use.  stability is very good, although as stated, it has a bit extra height and I had to add a tube stop to keep the OTA from dropping unexpectedly which Dobs do at times.  but it did that with the old base as well.

before:

 

 

after:

All the small dobs that I have used tend to shake a bit when I am focusing them. How does the DS base compare to the stock base in this situation, assuming that you aren’t moving around on the deck and causing it to shake? 



#18 Mike G.

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Posted 04 March 2021 - 01:44 PM

if you want real stability, you need to replace the commercial alt bearings with something 2-3x larger.  this is why you see most home-built and high end custom built dobs with the giant alt bearings.  movement is better with larger bearings and stability is also better.  but in lieu of that, just observe without touching the scope.  I find the object I want to look at, focus, then take my hands away from the scope until it needs to be bumped back into position.  I always observe seated so this helps as well.  especially at high magnifications, you shouldn't be touching the scope at all.  your heartbeat, pulsing veins, slight involuntary muscular movements, breathing, will all induce vibrations into a scope at 150x. if you have ever shot target rifles (I did for many years), you know that the body never stops moving, at least if you are alive.  anything you are connected to is going to absorb those movements.  focus, then take your hands off the scope.


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#19 James1996

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Posted 04 March 2021 - 01:46 PM

The focuser: You MAY want to consider whether the right move is to get a "low-profile" focuser like the ones shohin posted - they may be needed if you decide to get a binoviewer or hook up a camera. I can't answer this myself.

 

The finder: I found that after upgrading to a right-angle finder, I couldn't find anything. The one advantage of the contortions involved with a straight finder is that you're looking up at the sky and can roughly align the scope pretty well. With a RACI finder, I struggled to get even in the ballpark. The solution is to add a 1x finder (Telrad, Rigel, red-dot). This gives you the best of both worlds: Red dot gets you pretty (very) close, then you can use the RACI comfortably. I picked Rigel Quickfinder for my XT8-plus because there didn't seem to be room for a Telrad.

Ugh I couldn't stand the 6x30 straight through finder on my old Sky-Watcher Classic 150P back when I had it. (That was before I tripped at the top of the stairs outside and accidentally dropped it 8 feet down onto concrete breaking the primary mirror.) So I thought a 8/9x50 RACI would be better. So your suggesting that both a Rigel Quickfinder together and 8/9x50 RACI would work best?



#20 James1996

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Posted 04 March 2021 - 01:53 PM

if you want real stability, you need to replace the commercial alt bearings with something 2-3x larger.  this is why you see most home-built and high end custom built dobs with the giant alt bearings.  movement is better with larger bearings and stability is also better.  but in lieu of that, just observe without touching the scope.  I find the object I want to look at, focus, then take my hands away from the scope until it needs to be bumped back into position.  I always observe seated so this helps as well.  especially at high magnifications, you shouldn't be touching the scope at all.  your heartbeat, pulsing veins, slight involuntary muscular movements, breathing, will all induce vibrations into a scope at 150x. if you have ever shot target rifles (I did for many years), you know that the body never stops moving, at least if you are alive.  anything you are connected to is going to absorb those movements.  focus, then take your hands off the scope.

Huh I've never noticed any problems with stability on my XT8 even at 240x magnification. It's like the freaking Rock of Gibraltar in comparison to my old Orion Observer 70 AZ. scratchhead2.gif 


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#21 ayryq

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Posted 04 March 2021 - 02:21 PM

So your suggesting that both a Rigel Quickfinder together and 8/9x50 RACI would work best?

That's exactly what I do. I bought the RACI and couldn't find even the brightest reference stars. Maybe (probably) you're smarter than I am but for me it was no good. With the Rigel I can sometimes skip the RACI if I've got a wide-field eyepiece in, or if I'm looking at something bright (like a planet), but I still need the finder for starhopping like in Turn Left at Orion.

 

I like my Telrad (installed on my XT4.5) even better but I couldn't fit it in and didn't want to move anything or drill new holes in the tube, so I went with the Rigel. I have the adhesive partially doubled up so it sits partly on the front ring.

 

PXL_20210223_154838759.jpg

PXL_20210110_143937140.jpg

PXL_20210111_000541679.NIGHT.jpg

 

PS if you do use Turn Left at Orion, all the finder charts are reversed when you get the RACI. There are correct-image charts on the publisher's website.

 

PPS I have a great big weight attached with magnets to the rear of the tube, along with a battery pack for the fan. Between the bigger finder and the 82° eyepieces it's a lot of weight up front.


Edited by ayryq, 04 March 2021 - 02:24 PM.

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#22 shohin

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Posted 04 March 2021 - 02:24 PM

Hmm I think I'll buy this https://agenaastro.c...dual-speed.html and this https://agenaastro.c...mage-finder.htm. On second thought I can live with the current rocker box, the XT8 is already light enough I can comfortably carry it around my yard fully assembled. These possible upgrades for the XT8 might come later sometime this year. I'll first be buying a mount & diagonal for my AT80ED as well as new eyepieces for my scopes later this month.

GSO focusers are not a drop in fit to the XT8.  I think you'll have to fab an adapter and/or drill new holes.


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#23 ayryq

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Posted 04 March 2021 - 02:29 PM

GSO focusers are not a drop in fit to the XT8.  I think you'll have to fab an adapter and/or drill new holes.

Here's the page with specs: https://agenaastro.c...rd-focuser.html

Says "May work for some Orion XT dobsonian telescopes. Please measure hole spacing on your scope before purchase."
 


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#24 James1996

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Posted 04 March 2021 - 02:49 PM

GSO focusers are not a drop in fit to the XT8.  I think you'll have to fab an adapter and/or drill new holes.

Here's the page with specs: https://agenaastro.c...rd-focuser.html

Says "May work for some Orion XT dobsonian telescopes. Please measure hole spacing on your scope before purchase."
 

Oh! Just found this website (https://focuser.com/products.php) what about their focuser's? They sure look great aesthetically with nice build quality in the pictures.


Edited by James1996, 04 March 2021 - 02:53 PM.

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#25 scotsman328i

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Posted 04 March 2021 - 03:12 PM

Oh! Just found this website (https://focuser.com/products.php) what about their focuser's? They sure look great aesthetically with nice build quality in the pictures.

There are EXCELLENT focusers! I have one on my Orion XT8 Plus. Mine is in the violet color. If you did get one, you want the ‘MoonLite CR focuser with tri-knob and shift lock’. You will also need the Universal Install Kit for $69 that Ron makes also to guarantee a perfect fit to the Orion XT8 series scopes. This saves you from drilling any more holes into your scope body. Here’s a few images of mine I installed to my Orion. 
 

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