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Lets talk about the Meade SN-6 schmidt newt..

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#26 MtnGoat

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Posted 16 September 2011 - 04:17 PM

Nice setup john! You're really overboard on the tracking scope, I bet using double the FL of the SN6 really nails the tracking and them some.

That's the DSX version of the 90mm isn't it. Same one I have, I even did the same thing to piggyback it, the flat on the bottom is a very useful deal. I keep scouring CL waiting for someone to break loose with a 125mm. ;)

#27 MtnGoat

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Posted 16 September 2011 - 04:28 PM

Here's a shot from when I got started...I had the SN6 on a home made cradle riding an old 1.5" shaft Cave mount. Solid doesn't begin to describe it! Nothing like overmounting a scope, the wind could be howling and I could still image no problem.

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  • 4811421-CAVESN6c.jpg


#28 James Paulson

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Posted 16 September 2011 - 08:07 PM

I mounted an Orion motofocus to my stock focuser on my SN-6 and changed out the original finder for the mini finder-guider. Since I added the motofocus I have no focusing issues at all. I absolutely love my little SN-6 and its nice to read all these comments about it.
James

Attached Thumbnails

  • 4811727-Mini Guider.jpg


#29 hfjacinto

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Posted 16 September 2011 - 09:19 PM

[quote name="Patrick"]
Helder,

Why did you part with it? [/quote]

Patrick, after purchasing the Orion EON, I didn't use the SN6 as much. The 3 main issues with it are:

1) With the 80MM Eon as a guider it was hard to balance.
2) There is a drop off in illumination from the center to the edge. And while flats help, there was always some residual vignetting that was hard to remove on images that had 5 minute subs (remember I am using the Orion Star Shoot which has a chip size of 25MM by 17.7 MM compared to a KAF 8300 chip at 18MM by 13.5.)
3)Although I don't get diffration spikes on stars, you do get the shadow of the secondary.

[quote] I've looked at the SN6 over the years, but have never been willing to pull the trigger on one. They're certainly cute, but is there enough field illumination for an APS sized sensor? [/quote]

I believe there is, for larger chips there is some vignetting.

[quote] Or is there a lot of light drop off? [/quote]

There is vignetting on longer exposures, on short exposures, its not as noticable.

[quote] My C6 SCT with focal reducer gets me down to around 960mm f/l at f/6.3. Is it worth it to get an SN6 to drop down to f/5 and 750mm f/l or is it a little redundant? [/quote]

I think the SN6 is better for imaging than a SCT becuase:
1) Its F5
2) Very flat field
3) With a moonlight no focus shift or issues.
4) With the 50MM Guider, it should be easy to balance
5) ITS F5
6) A Baader MPCC will fix any oblong stars (not that it has much issues).

[quote] Does the SN6 have a flatter field than an SCT? [/quote]

See below images

[quote] What are the advantages/disadvantages of one over the other? [/quote]

Biggest is faster and no focus shift.

Patrick [/quote]

Attached Thumbnails

  • 4811844-M31 -2  Photoshoped.jpg


#30 hfjacinto

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Posted 16 September 2011 - 09:23 PM

M27

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  • 4811851-M27_reprocessed.jpg


#31 hfjacinto

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Posted 16 September 2011 - 09:26 PM

Veil

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  • 4811861-Veil for CN.jpg


#32 hfjacinto

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Posted 16 September 2011 - 09:29 PM

To get a better imaging scope, you have to spend over $1000. So the SN6 is a BARGAIN..

#33 Patrick

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Posted 17 September 2011 - 08:02 AM

MtnGoat,

Nice Andromeda! Is that a full frame shot or have you cropped it?

Patrick

#34 Patrick

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Posted 17 September 2011 - 08:03 AM

Helder,

Nice shots! Is your M27 a full frame shot or have you cropped it?

Patrick

#35 Patrick

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Posted 17 September 2011 - 08:38 AM

2) There is a drop off in illumination from the center to the edge. And while flats help, there was always some residual vignetting that was hard to remove on images that had 5 minute subs (remember I am using the Orion Star Shoot which has a chip size of 25MM by 17.7 MM compared to a KAF 8300 chip at 18MM by 13.5.)



The Orion Starshoot uses an APS sized sensor, which would be the same as my Canon 60D.

John Graham,

What is your experience with the SN6 and APS sized sensors regarding vignetting? Is it an issue to be concerned about?

I think the SN6 is better for imaging than a SCT becuase:
1) Its F5
2) Very flat field
3) With a moonlight no focus shift or issues.
4) With the 50MM Guider, it should be easy to balance
5) ITS F5
6) A Baader MPCC will fix any oblong stars (not that it has much issues).



I'm trying to justify purchasing the SN6 given I already have a C6 SCT. The f/5 vs f/6.3 could be an issue, but it's not light years difference. Flat field and non-bloated stars at the edges may be one major advantage. The 750mm focal length is a nice place to be. I'd want to use this scope non-guided on my Vixen GP2 (+/- 7 arc second PE)...focal length may be too long for that though. 1 minute subs?? f/5 vs v/6.3 may be significant then.

I think one main advantage of the SN6 over the C6 SCT is that the baffle tube is 27mm on the C6 whereas the secondary diagonal on the SN6 is 2.14"...much larger! I think there is significant vignetting on the SCT because of the baffle tube issue.

Image shift on a C6 SCT is not an issue as there is very little.

Patrick

#36 Jb32828

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Posted 17 September 2011 - 09:55 AM

My pics had vignetting with my 10" Meade SCT, they have had vignetting with the SN-6. Honestly, I am not in the market, and probably will never be in the market for a 130mm + apochromat refractor so I take flats and compensate for it. Heck, there is obvious light drop-off even when I take wide fields with just the camera and a 300mm lens. I wouldn't sweat the vignetting and instead be thinking of the bargain at 199.00 that scope is and just suffer through ten minutes of taking flats.

#37 MtnGoat

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Posted 17 September 2011 - 10:08 AM

MtnGoat,

Nice Andromeda! Is that a full frame shot or have you cropped it?

Patrick


Thanks Patrick, I can't take all the credit here...it's my scope and mount and my buddy Jeff's Nikon, so it was a joint effort.

I don't think it's cropped, but it is binned 2x2.

#38 jgraham

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Posted 17 September 2011 - 10:24 AM

Yep, there is some vignetting when I use my Rebel XTi, but I'm not sure if it's from the scope or from the 1.25" nose piece fitted with an 1.25" IDAS LPS-2 filter. Personally, I suspect it's the nose piece. In any case, flats cleans it right up. It would be interesting to compare you C6 at f/6.3 with my SN6 at f/5. This big diference is that the C6 was designed to operate at f/10 while the SN6 was designed to operate at f/5, so I suspect the SN6 would have the edge, but it may not be a big edge. As far as the cost, jeesh, the finder is worth $70 and I'm going to convert it into a guide scope. :)

Recently, I've been doing a lot of narrowband bi-color imaging with my LXD75 SN6. The weather was iffy this past Thursday evening, so I switched back to broadband image for a couple of quick shots. This is a quickie of M2...

M2 – Globular Cluster in Aquarius
Telescope: Meade LXD75 SN6
Luminance: Meade DSI Pro III, 32x45sec, IDAS LPS-2 Filter
Color: Meade DSI III, 16x60sec, Orion Imaging Filter
Guide scope: Meade DSX-90, PHD
Software: Envisage, Autostar Image Processing, Nebulosity, Photoshop

Attached Thumbnails

  • 4812580-M2 (9-15-2011)j.JPG


#39 hfjacinto

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Posted 17 September 2011 - 10:59 AM

Patrick, APS range from 20.7×13.8 mm to 28.7×19.1 mm

So it might be large, might be smaller. Compared to my friends Canon, my chip is huge.

I have to say for $199 this scope is a bargain, when I purchased mine, I spent over $400 for it, add in the moonlight, bobs knobs, finder, laser collimator, dew shield and bobs knobs, I think I undercharged Jason :(

;)

#40 94bamf

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Posted 17 September 2011 - 11:48 AM

Ken,

One more thing, swapping out the secondary won't do anything for you. Remember it has a corrector plate to hold the secondary, the hole where the secondary is will still be there. Get some bob's knobs also.


Thanks for the pictures Helder. I got the idea of swapping in a smaller secondary because several of the pictures I had seen on the net appeared to show the secondary mirror itself being much larger than the plug/holder in the middle of the corrector. Your pictures seem to show that is not the case. Already ordered the Bobs Knobs, I can't believe they are $25. I could probably find something at the hardware store, but what the heck I didn't wanna mess with it. Maybe these are less common, so Bob charges more for them.. :grin:

I still haven't got a ship notice from Meade yet. Hope they actually have these scopes in stock.. :foreheadslap:

I also want to thank everybody else for all the added info to this thread. Maybe I will give AP a shot with this scope, although I am afraid to get started down that road.. :lol:

Ken

#41 MtnGoat

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Posted 17 September 2011 - 01:19 PM

Yes, be afraid be very afraid. It's an addiction. I started out visual, then got an ETX for a hundred bucks, then thought what the heck and picked up a DSI on a lark. Then I stuck it on the ETX, gotoed M51, started the DSI up..15 minutes later it was all over. 6 months later I had progressed past my SN6 to an SN8 on an LXD75, the yard had sprouted not one but two concrete piers, and my wife is wondering what the heck happened!

#42 Patrick

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Posted 18 September 2011 - 11:13 AM

OKAY...I GIVE UP.

...JUST ORDERED THE SN-6. :mad:

Just what I need...another scope... :bawling:

Thanks alot guys...

Patrick :grin:

#43 Patrick

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Posted 18 September 2011 - 11:19 AM

And, another thing...I was getting out of astrophotography...and now it's your fault that I'm not. What am I supposed to tell the wife? Answer me that... :confused:

Patrick ;)

#44 jmiele

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Posted 18 September 2011 - 11:20 AM

Won't it just blend in with the rest? :)
Joe

#45 laconicsax

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Posted 18 September 2011 - 02:31 PM

Thanks for the heads-up on the sale! Just ordered one...here's hoping that it's still in stock and ships.

#46 IDONTSEEIT

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Posted 19 September 2011 - 04:33 AM

Hi All,


For visual only(no particular objects in mind, just general stargazing, etc.), would this be better or worse than the C-6(SCT)?

Thanks,

#47 James Paulson

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Posted 19 September 2011 - 04:55 AM

Hi All,


For visual only(no particular objects in mind, just general stargazing, etc.), would this be better or worse than the C-6(SCT)?

Thanks,


Hard to answer that one. It is an f/5 instrument with a shorter focal length, so the field of view is much wider at the tradeoff of lower magnification. Also because it is mounted on a GEM eyepiece positions may seem awkward to some but certainly not excessively high.

YMMV.

James

#48 jgraham

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Posted 19 September 2011 - 06:47 AM

Cool-down of the SN6 will be a tad faster. With a native f/5 design the SN6 should perform better at low power and wide fields. It handles a Barlow/Powermate pretty well so it handles the high end fine. Sooo, overall you may find the differences for visual fairly modest.

#49 Patrick

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Posted 19 September 2011 - 09:42 AM

For visual only(no particular objects in mind, just general stargazing, etc.), would this be better or worse than the C-6(SCT)?



For visual only, I think the C6 would be a more versatile instrument. Collimation is less difficult and mounting is less of a concern. Having the diagonal on the back of the scope on the C6 makes it more comfortable to use. With my Denkmeier S1 Power X Switch focal reducer and TV 27 Pan, I can get about 1.5-1.6 deg true field of view in the C6. The C6 will cool down fairly quickly. Since I have the C6, I'll probably continue using it for visual, since it works so well.

For me the SN6 is all about astrophotography. I've never used an SN scope, so my opinion may change after I get used to it. However, I have used a number of Newtonians on EQ mounts, and I don't anticipate a lot of difference from those. The SN6 should be very similar to a standard 6" f/5 Newtonian, but be better corrected for coma on the outer edges of the fov. For planetary and high mag viewing the SCT should be better, but I could be wrong...I'll let you know after I get the scope and make a comparion. :smirk:

Patrick

#50 94bamf

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Posted 19 September 2011 - 10:21 AM

For visual only(no particular objects in mind, just general stargazing, etc.), would this be better or worse than the C-6(SCT)?



For visual only, I think the C6 would be a more versatile instrument. Collimation is less difficult and mounting is less of a concern. Having the diagonal on the back of the scope on the C6 makes it more comfortable to use. With my Denkmeier S1 Power X Switch focal reducer and TV 27 Pan, I can get about 1.5-1.6 deg true field of view in the C6. The C6 will cool down fairly quickly. Since I have the C6, I'll probably continue using it for visual, since it works so well.

For me the SN6 is all about astrophotography. I've never used an SN scope, so my opinion may change after I get used to it. However, I have used a number of Newtonians on EQ mounts, and I don't anticipate a lot of difference from those. The SN6 should be very similar to a standard 6" f/5 Newtonian, but be better corrected for coma on the outer edges of the fov. For planetary and high mag viewing the SCT should be better, but I could be wrong...I'll let you know after I get the scope and make a comparion. :smirk:

Patrick


I have both scopes also, looking forward to making the comparison. I would probably disagree about collimation being harder on the SN. Unless I am missing something, I don't see collimation being any different than on a Newtonian, which I have the proper tools to make quick work of. I don't consider SCT collimation "hard", but I do find it more time consuming. It can be quit difficult to get it dialed in, in poor seeing conditions, which seem to be common around here. The main advantage to SCT collimation is that it isn't require very often. I agree the C6 is a snap to mount, and very easy to use compared to a newt on a GEM. My C6 is very good optically, it would be tough for the SN-6 to outperform it, but I will keep my fingers crossed.

Ken

EDIT... Maybe I was missing something on the collimation of the SN. :lol: Check out this LINK. I am not convinced it will require that much work, I will report back once I give it a shot.. :grin:


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