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#26 Nicole Sharp

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Posted 25 November 2018 - 08:43 PM

Do I need to get a dew heater in winter?  Or can I wait until it gets warmer for that?



#27 Nicole Sharp

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Posted 26 November 2018 - 05:34 AM

Anyone know if the iOptron 1.5" tripod bag will fit a Nexstar 5SE tripod?

 

https://www.ioptron....duct-p/3404.htm

 

Other recommendations for tripod carry bags?



#28 Nicole Sharp

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Posted 26 November 2018 - 05:36 AM

Anyone know if a Star Analyzer spectral filter would work in a C5 without a reducer?  Or is the f/10 focal ratio not fast enough?



#29 Noah4x4

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Posted 26 November 2018 - 06:18 AM

Hi Nicole,

 

Totting up what you propose to spend suggests to me that you instead ought to be seeking a superior mount/tripod and cut down on accessories if budget is a concern. The SE range lacks a robust tripod, has cheap plastic gears, has loads of backlash and you will probably hate it if you move onto EAA or AP.  The Evolution is vastly superior. 

 

But with any Alt-Az you need a wedge or Hyperstar for decent quality EAA or AP far more so than filters and other more limited paraphernalia. Loading a less robust SE tripod with a (15lbs) wedge is not ideal, and a 5" OTA is too small for Hyperstar and most cameras. Frankly, I wish I had bought a decent GEM, but am content with short exposures on my 8" Evolution with Hyperstar having ditched the wedge. 

 

I built a large inventory of expensive gear (see my signature) that is today largely redundant. In under three years, my previously relatively rural property became surrounded by 6,000 light polluting new houses. I could no longer see even 'faint fuzzies' through an eyepiece. So I switched to EAA and Hyperstar. However, I could not have predicted that would be my destiny at the same stage of my equipment development to you.

 

My advice is hence to focus on tripod, mount and OTA and perhaps two eyepieces. If conditions dictate, maybe a dew shield/heater. But forget the rest until you build experience of your new rig and can determine where IT will next take you towards your next destiny. Mine took me into 4K UHD EAA viewing. That is yet another dimension.


Edited by Noah4x4, 26 November 2018 - 06:19 AM.


#30 Nicole Sharp

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Posted 26 November 2018 - 06:27 AM

I just saw that ProTelescope sells a 1080p wifi camera.  It's only 24 FPS though but it works with Android, so no laptop needed.  It's about the same price as the 560p30 Revolution Imager.  Any idea if it's any good, or if I should just use a DSLR instead?

 

Yes, my primary goal with the 5SE is just Solar-System imaging.  But it would be cool to grab some spectral lines if possible.  But I think the Star Analyzer does need longer exposures to work unfortunately.  But if the object is really bright, like Sirius or Jupiter, it might be okay?  It would make looking at stars a lot more interesting to see what they are made of instead of just seeing a little dot.


Edited by Nicole Sharp, 26 November 2018 - 06:29 AM.


#31 Frank Otsuka

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Posted 26 November 2018 - 06:34 AM

I used the .63x on a C5 (with solar filter) on the great solar eclipse of 2017. I took the C5 from Arizona to Idaho because it was the most portable.  It framed the sun quite well, but there were slight internal reflections in the  image from the added glass. In my case, vignetting was not a problem (APS-C). Having said that, I use the .63x more often on an 8" and 10" SCT, as the baffle tubes are larger. Visually, a 32 mm added to this reducer puts you in the situation where you can "see" the secondary blob in the middle of the view. Mostly annoying.


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#32 Nicole Sharp

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Posted 26 November 2018 - 07:30 AM

Is a SkySync GPS necessary for a 5SE?  If I did the math right, a Canon APS-C camera and a 5X Barlow should have a field of view of about 7 arcminutes.  Inputting the time manually to within (+/-) 2 seconds should then correspond to a positional error of about (+/-) 1 arcminute?  So then GOTO would find the target within 7 (+/-) 1 arcminutes even at 231X magnification?  That doesn't seem so bad but I think the SE mount has a lot more error than from just the time input.


Edited by Nicole Sharp, 26 November 2018 - 07:34 AM.


#33 Nicole Sharp

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Posted 26 November 2018 - 07:33 AM

I used the .63x on a C5 (with solar filter) on the great solar eclipse of 2017. I took the C5 from Arizona to Idaho because it was the most portable.  It framed the sun quite well, but there were slight internal reflections in the  image from the added glass. In my case, vignetting was not a problem (APS-C). Having said that, I use the .63x more often on an 8" and 10" SCT, as the baffle tubes are larger. Visually, a 32 mm added to this reducer puts you in the situation where you can "see" the secondary blob in the middle of the view. Mostly annoying.

Thanks for that info.  So sounds like it would be a waste of money for both visual and photographic use, unless I was using a small-sensor camera  (17 mm or smaller).



#34 Nicole Sharp

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Posted 26 November 2018 - 07:42 AM

I used the .63x on a C5 (with solar filter) on the great solar eclipse of 2017. I took the C5 from Arizona to Idaho because it was the most portable.  It framed the sun quite well, but there were slight internal reflections in the  image from the added glass. In my case, vignetting was not a problem (APS-C). Having said that, I use the .63x more often on an 8" and 10" SCT, as the baffle tubes are larger. Visually, a 32 mm added to this reducer puts you in the situation where you can "see" the secondary blob in the middle of the view. Mostly annoying.

For a total Solar eclipse, I definitely plan to use a telephoto lens instead, since I want to capture the Solar corona (it's really big).

 

There is a Solar transit of the ISS visible here coming up next month though.  The angular speed of the ISS is so fast, that I want the full disc of Sol in the field of view to be able to capture as many frames as possible (I think it moves too fast to actually track the orbit without exceeding the maximum slew rate).  Would a SkySync GPS help there?  I think the edge of the Solar disc will be about 7 arcminutes from the edge of the camera sensor with Canon APS-C.



#35 Nicole Sharp

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Posted 26 November 2018 - 09:04 AM

Really confused about focusing masks here.  Just from Farpoint and Astrozap alone, I see three different designs.  Which might be the best for a 5SE?  Specifically need it for Solar observing when there are no sunspots, so it needs to be able to fit over the Solar filter.  Is that even safe though if using a film filter?


Edited by Nicole Sharp, 26 November 2018 - 09:12 AM.


#36 Nicole Sharp

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Posted 26 November 2018 - 09:22 AM

How helpful would a comet filter be for Wirtanen next month?  Waste of money?  I didn't get the Mars filter for Mars.



#37 Nicole Sharp

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Posted 26 November 2018 - 09:23 AM

Any opinions on this thing?  Waste of money?

 

https://farpointastr...holder-nexstar/


Edited by Nicole Sharp, 26 November 2018 - 09:24 AM.


#38 Night shift

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Posted 26 November 2018 - 09:41 AM

  Good morning Nicole. If you have your heart set on the 5SE there is one you can look at on the CN classifieds.  Add #154530. It is priced correctly with some of the accessories you are looking for.  Good luck in your endeavor.  



#39 jallbery

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Posted 26 November 2018 - 10:09 AM

You are getting ahead of yourself and trying to solve problems you don't even know exist.  Buy the scope.  Learn to use it.  Figure out what you really need.

 

A minor time error (plus or minus a few seconds) will be corrected by the alignment procedure.   GPS is merely a convenience (it auto enters time, latitude and longitude).  Even a simple solar system alignment will result in tracking that keeps an object in view for tens of minutes and probably longer.

 

I doubt a focusing mask is necessary for solar or lunar with a DSLR.  Take some pictures;  see if they are in focus; adjust accordingly.   Backyard EOS can also help considerably, I believe.

 

Using a 5X barlow with a DSLR makes little sense to me.  At 2X you probably have captured the scope's full resolution with any modern DSLR.  Blowing things up further will have little to no benefit.   And for an ISS transit, I'd use video to record the transit.   Use as fast as frame rate as you can, and let the ISS cross the sun.

 

Yes, a C5 with F/6.3 R/C will vignette with a crop sensor camera, but it's not like it is dark in the corners.  You may also want to crop the photos square.  Either way, you may still appreciate the extra space from a compositional standpoint.  And visually, for night time astronomy, I was surprised how well the combo works.  Yes there is detectable falloff at the field edges with a max-field  1.25" eyepiece, but there is useful illumination to the edge.   In the day time, I could see how the 5.6mm exit pupil would cause problems for people (your day-time pupil can't accommodate the exit pupil, so it effectively stops down the scope, making the secondary even harder to ignore), but I find the combo usable at night with even my 35mm Ultima.   Different people have different sensitivities to the shadow of the secondary, though. 

 

The R/C also provides some minor field flattening, which may be desirable even if you end up re-cropping the picture.

 

As far as dew, that is location dependent.   A simple LED dimmer can be used as a dew controller (search the forums, and you can find a post on the subject) at substantially lower cost than most commercial controllers.   Or you can start with just a dew shield (which is helpful for cutting down stray reflections as well).   As far as winter, in Michigan, you can frost your corrector on a cold winter night.

 

And cord wrap is always going to be a minor issue with the 5SE with an external power source, unless you use something that you can strap to the arm of the mount.  It's not that big of deal though-- just something to be aware of.   However, if you want to avoid it, you can use something like this:

https://www.amazon.c...ium ion battery

 

Attach it to the mount with velcro.   I've also seen people use velcro to allow the hand controller to be mounted places other than the provided location on the side of the arm (like on the arm but so it faces you).



#40 Nicole Sharp

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Posted 26 November 2018 - 10:15 AM

You are getting ahead of yourself and trying to solve problems you don't even know exist.  Buy the scope.  Learn to use it.  Figure out what you really need.

 

A minor time error (plus or minus a few seconds) will be corrected by the alignment procedure.   GPS is merely a convenience (it auto enters time, latitude and longitude).  Even a simple solar system alignment will result in tracking that keeps an object in view for tens of minutes and probably longer.

 

I doubt a focusing mask is necessary for solar or lunar with a DSLR.  Take some pictures;  see if they are in focus; adjust accordingly.   Backyard EOS can also help considerably, I believe.

 

Using a 5X barlow with a DSLR makes little sense to me.  At 2X you probably have captured the scope's full resolution with any modern DSLR.  Blowing things up further will have little to no benefit.   And for an ISS transit, I'd use video to record the transit.   Use as fast as frame rate as you can, and let the ISS cross the sun.

 

Yes, a C5 with F/6.3 R/C will vignette with a crop sensor camera, but it's not like it is dark in the corners.  You may also want to crop the photos square.  Either way, you may still appreciate the extra space from a compositional standpoint.  And visually, for night time astronomy, I was surprised how well the combo works.  Yes there is detectable falloff at the field edges with a max-field  1.25" eyepiece, but there is useful illumination to the edge.   In the day time, I could see how the 5.6mm exit pupil would cause problems for people (your day-time pupil can't accommodate the exit pupil, so it effectively stops down the scope, making the secondary even harder to ignore), but I find the combo usable at night with even my 35mm Ultima.   Different people have different sensitivities to the shadow of the secondary, though. 

 

The R/C also provides some minor field flattening, which may be desirable even if you end up re-cropping the picture.

 

As far as dew, that is location dependent.   A simple LED dimmer can be used as a dew controller (search the forums, and you can find a post on the subject) at substantially lower cost than most commercial controllers.   Or you can start with just a dew shield (which is helpful for cutting down stray reflections as well).   As far as winter, in Michigan, you can frost your corrector on a cold winter night.

 

And cord wrap is always going to be a minor issue with the 5SE with an external power source, unless you use something that you can strap to the arm of the mount.  It's not that big of deal though-- just something to be aware of.   However, if you want to avoid it, you can use something like this:

https://www.amazon.c...ium ion battery

 

Attach it to the mount with velcro.   I've also seen people use velcro to allow the hand controller to be mounted places other than the provided location on the side of the arm (like on the arm but so it faces you).

 

I just learned what exit pupil is the other day, but it is still a bit confusing.  If I want to get just one eyepiece with a low magnification and a wide AFOV, and then Barlow it for higher magnifications, what would be the best focal length for an eyepiece with the C5?  I figured a 52-degree AFOV 32-mm eyepiece would be best.  No?  The exit pupil with a 32-mm eyepiece at f/10 would be 3 mm.  What would a 3-mm exit pupil mean for visual use and for afocal photography with a cameraphone (1/3-inch sensor, 8 mm in diagonal)?



#41 Nicole Sharp

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Posted 26 November 2018 - 10:22 AM

You are getting ahead of yourself and trying to solve problems you don't even know exist.  Buy the scope.  Learn to use it.  Figure out what you really need.

 

A minor time error (plus or minus a few seconds) will be corrected by the alignment procedure.   GPS is merely a convenience (it auto enters time, latitude and longitude).  Even a simple solar system alignment will result in tracking that keeps an object in view for tens of minutes and probably longer.

 

I doubt a focusing mask is necessary for solar or lunar with a DSLR.  Take some pictures;  see if they are in focus; adjust accordingly.   Backyard EOS can also help considerably, I believe.

 

Using a 5X barlow with a DSLR makes little sense to me.  At 2X you probably have captured the scope's full resolution with any modern DSLR.  Blowing things up further will have little to no benefit.   And for an ISS transit, I'd use video to record the transit.   Use as fast as frame rate as you can, and let the ISS cross the sun.

 

Yes, a C5 with F/6.3 R/C will vignette with a crop sensor camera, but it's not like it is dark in the corners.  You may also want to crop the photos square.  Either way, you may still appreciate the extra space from a compositional standpoint.  And visually, for night time astronomy, I was surprised how well the combo works.  Yes there is detectable falloff at the field edges with a max-field  1.25" eyepiece, but there is useful illumination to the edge.   In the day time, I could see how the 5.6mm exit pupil would cause problems for people (your day-time pupil can't accommodate the exit pupil, so it effectively stops down the scope, making the secondary even harder to ignore), but I find the combo usable at night with even my 35mm Ultima.   Different people have different sensitivities to the shadow of the secondary, though. 

 

The R/C also provides some minor field flattening, which may be desirable even if you end up re-cropping the picture.

 

As far as dew, that is location dependent.   A simple LED dimmer can be used as a dew controller (search the forums, and you can find a post on the subject) at substantially lower cost than most commercial controllers.   Or you can start with just a dew shield (which is helpful for cutting down stray reflections as well).   As far as winter, in Michigan, you can frost your corrector on a cold winter night.

 

And cord wrap is always going to be a minor issue with the 5SE with an external power source, unless you use something that you can strap to the arm of the mount.  It's not that big of deal though-- just something to be aware of.   However, if you want to avoid it, you can use something like this:

https://www.amazon.c...ium ion battery

 

Attach it to the mount with velcro.   I've also seen people use velcro to allow the hand controller to be mounted places other than the provided location on the side of the arm (like on the arm but so it faces you).

 

About the cord wrap, I was just thinking of that.  Would it be less annoying to have a power source strapped to the leg of the tripod, that I have to take off and reattach to a different leg to avoid getting wrapped around the tripod, or to have a power source that sits on the ground I can pick up and move to avoid cord wrap?  My biggest concern with anything sitting on the ground would be bugs that might be attracted to the warmth of the electronics, and of course there might be other things on the ground I may not want to get on a power supply.



#42 Nicole Sharp

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Posted 26 November 2018 - 10:32 AM

This is what I have on the shopping list so far:

 

Celestron Sky Maps

Celestron Nexstar 5SE

Celestron mount/OTA carry case

Farpoint desiccant cap

Farpoint dry pack

Astrozap dew shield

 

Still looking for:

 

power supply

tripod bag (iOptron?)

handcontroller case (not sure if this will work for the 5SE though)

32-mm? eyepiece

Solar filter (Astrozap? Baader?)

focusing mask (Astrozap? Farpoint? ---not sure if this will work with a Solar filter)

2X Barlow (no 3X or 5X?)

24-mm reticle eyepiece

GPS (SkySync? USB dongle? no GPS?)

Telegizmos Solar cover

T-adapted prime-focus camera (M50? SL2? Sony?)

 

What's the best way to use a reticle eyepiece for accurate Solar alignment?  Or would I have to use a reticle finderscope instead so the disc appears small enough to accurately center?  Or is it easier to just try to get the field of view to about 0.5 degrees, and then center the disc?


Edited by Nicole Sharp, 26 November 2018 - 10:40 AM.


#43 jallbery

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Posted 26 November 2018 - 10:44 AM

I've never found cord wrap to be anything more than a minor nuisance.  If by choice of targets I  get close to all the way around the scope, I just slew to unwind.


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#44 Nicole Sharp

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Posted 26 November 2018 - 10:46 AM

You are getting ahead of yourself and trying to solve problems you don't even know exist.  Buy the scope.  Learn to use it.  Figure out what you really need.

 

A minor time error (plus or minus a few seconds) will be corrected by the alignment procedure.   GPS is merely a convenience (it auto enters time, latitude and longitude).  Even a simple solar system alignment will result in tracking that keeps an object in view for tens of minutes and probably longer.

 

I doubt a focusing mask is necessary for solar or lunar with a DSLR.  Take some pictures;  see if they are in focus; adjust accordingly.   Backyard EOS can also help considerably, I believe.

 

Using a 5X barlow with a DSLR makes little sense to me.  At 2X you probably have captured the scope's full resolution with any modern DSLR.  Blowing things up further will have little to no benefit.   And for an ISS transit, I'd use video to record the transit.   Use as fast as frame rate as you can, and let the ISS cross the sun.

 

Yes, a C5 with F/6.3 R/C will vignette with a crop sensor camera, but it's not like it is dark in the corners.  You may also want to crop the photos square.  Either way, you may still appreciate the extra space from a compositional standpoint.  And visually, for night time astronomy, I was surprised how well the combo works.  Yes there is detectable falloff at the field edges with a max-field  1.25" eyepiece, but there is useful illumination to the edge.   In the day time, I could see how the 5.6mm exit pupil would cause problems for people (your day-time pupil can't accommodate the exit pupil, so it effectively stops down the scope, making the secondary even harder to ignore), but I find the combo usable at night with even my 35mm Ultima.   Different people have different sensitivities to the shadow of the secondary, though. 

 

The R/C also provides some minor field flattening, which may be desirable even if you end up re-cropping the picture.

 

As far as dew, that is location dependent.   A simple LED dimmer can be used as a dew controller (search the forums, and you can find a post on the subject) at substantially lower cost than most commercial controllers.   Or you can start with just a dew shield (which is helpful for cutting down stray reflections as well).   As far as winter, in Michigan, you can frost your corrector on a cold winter night.

 

And cord wrap is always going to be a minor issue with the 5SE with an external power source, unless you use something that you can strap to the arm of the mount.  It's not that big of deal though-- just something to be aware of.   However, if you want to avoid it, you can use something like this:

https://www.amazon.c...ium ion battery

 

Attach it to the mount with velcro.   I've also seen people use velcro to allow the hand controller to be mounted places other than the provided location on the side of the arm (like on the arm but so it faces you).

 

Under what conditions would I need to worry about frost?  I live in the Appalachian Mountains, and I've seen it get down to almost negative twenty degrees Fahrenheit in December, but I would not want to do any observing below freezing if I can avoid it, both for the electronics as well as my health.  The major exceptions coming up are the ISS Solar transit on December 21 (3 PM) and the total Lunar eclipse on January 21 (1 AM---very very cold).  I might even want to get a StarSense for the total Lunar eclipse if it means I can sit in the car while the telescope aligns itself :-O .



#45 jallbery

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Posted 26 November 2018 - 11:07 AM

Under what conditions would I need to worry about frost?  I live in the Appalachian Mountains, and I've seen it get down to almost negative twenty degrees Fahrenheit in December, but I would not want to do any observing below freezing if I can avoid it, both for the electronics as well as my health.  The major exceptions coming up are the ISS Solar transit on December 21 (3 PM) and the total Lunar eclipse on January 21 (1 AM---very very cold).  I might even want to get a StarSense for the total Lunar eclipse if it means I can sit in the car while the telescope aligns itself :-O .

If you ever plan to use your scope when you might need an ice scraper the next morning if your car is not parked in a garage, you may need to worry about frost.

 

Also, if you are using things like focusing masks on a cold night, and happen to breath close to the corrector plate...



#46 jallbery

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Posted 26 November 2018 - 11:23 AM

And as far as eyepieces...    For my 5SE, I have a grab-and-go eyepiece kit with some Celestron "Halloween" plossls (32, 26, 17, 12.5mm), a 2X barlow, and the R/C.   If it's a good night for planetary or other high-power work (or for splitting doubles), I'll use the barlow with the the 17 or 12.5mm).  I don't like barlows for ergonomic reasons, but I like the short eye relief of plossls under 10mm even less.

 

The 5SE comes with a 25mm plossl, I believe.   Add a 32mm and 15mm plossl, and a GSO shorty 2X barlow, and you'll have a workable set.   The barlow element unscrews and can be screwed into an eyepiece for about a 1.5X boost.   You also should be able to screw it into the diagnoal (I think), which should give you more than a 2X increase.

 

I think a single 32mm plossl and a barlow is a bad idea.   Barlows usually work best with shorter focal length eyepieces. 

 

You don't need anything more exotic than decent plossls for a c5 (IMO), and more expensive widefields will make the field curvature and coma of the scope more evident than using a narrower, lower-powered eyepiece.  YMMV.

 

Another nice thing about a set of plossls with a C5-- they are lightweight and don't create balance issues.   Also, since it is a scaled design, it's easy to tell which one is which in the dark.


Edited by jallbery, 26 November 2018 - 11:29 AM.


#47 jallbery

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Posted 26 November 2018 - 11:28 AM

As far as exit pupils...

https://www.skyandte...a-pupil-primer/

https://www.cloudyni...xit-pupil-size/



#48 Nicole Sharp

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Posted 26 November 2018 - 12:25 PM

And as far as eyepieces...    For my 5SE, I have a grab-and-go eyepiece kit with some Celestron "Halloween" plossls (32, 26, 17, 12.5mm), a 2X barlow, and the R/C.   If it's a good night for planetary or other high-power work (or for splitting doubles), I'll use the barlow with the the 17 or 12.5mm).  I don't like barlows for ergonomic reasons, but I like the short eye relief of plossls under 10mm even less.

 

The 5SE comes with a 25mm plossl, I believe.   Add a 32mm and 15mm plossl, and a GSO shorty 2X barlow, and you'll have a workable set.   The barlow element unscrews and can be screwed into an eyepiece for about a 1.5X boost.   You also should be able to screw it into the diagnoal (I think), which should give you more than a 2X increase.

 

I think a single 32mm plossl and a barlow is a bad idea.   Barlows usually work best with shorter focal length eyepieces. 

 

You don't need anything more exotic than decent plossls for a c5 (IMO), and more expensive widefields will make the field curvature and coma of the scope more evident than using a narrower, lower-powered eyepiece.  YMMV.

 

Another nice thing about a set of plossls with a C5-- they are lightweight and don't create balance issues.   Also, since it is a scaled design, it's easy to tell which one is which in the dark.

 

I didn't think of that.  If I balance and align the telescope with a 32-mm or 24-mm eyepiece, and then I add a Barlow, that will shift the center of mass by about 8%.  Yet another contribution to tracking errors on the budget mount.

 

I liked the idea of getting one nice eyepiece, and then one or two nice Barlows (I was planning to get the heavier apochromatic ones, so I can use them for prime-focus imaging).  But the low-weight OTA (compared to say a C8) means that adding and removing components would have a larger contribution to imbalance than it would on a heavier OTA.  But maintaining the same AFOV and eyerelief is important for afocal imaging.  If the AFOV is too small, it will vignette the afocal photographs.

 

A number of people have recommended I get the Celestron zoom eyepiece.  That would keep the weight constant, and it doesn't have terrible eyerelief.  But the apparent field of view goes down to 40 degrees at higher magnifications.  From the telescope I have now, I know that will create vignetting problems for afocal imaging.  It likely wouldn't matter for planets against a dark background, but for Solar and Lunar imaging it would.  Otherwise I would have to invest in expensive wide-field eyepieces, and if you want both wide AFOV and long eyerelief, that can cost a lot.  A more serious problem when using an afocal adapter is that if the eyerelief is shorter on one eyepiece compared to another, you have to realign the camera.  If the eyerelief is constant between two eyepieces, you can interchange them without needing to realign the camera.

 

I still need to get an eyepiece case at some point though rather than carrying eyepieces around jumbled in a backpack.  I heard some negative feedback though that the Orion eyepiece case won't take certain eyepieces? 


Edited by Nicole Sharp, 26 November 2018 - 12:36 PM.


#49 jallbery

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Posted 26 November 2018 - 12:42 PM

The kits have a bunch of short focal length plossls that are of limited value.   I have the Celestron (or maybe its the Meade-branded one) zoom and its primary use for me is as a dust plug.  Other people like it though.  

 

I would not assume that eye relief stays constant when you use the zoom.  Plus it probably changes length (depending on how you mount the camera).   Parfocal eyepieces with constant eye relief will be different physical lengths as well.



#50 Nicole Sharp

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Posted 26 November 2018 - 01:02 PM

The kits have a bunch of short focal length plossls that are of limited value.   I have the Celestron (or maybe its the Meade-branded one) zoom and its primary use for me is as a dust plug.  Other people like it though.  

 

I would not assume that eye relief stays constant when you use the zoom.  Plus it probably changes length (depending on how you mount the camera).   Parfocal eyepieces with constant eye relief will be different physical lengths as well.

 

I am not crazy about the selections of focal lengths for the eyepiece kits either.  I mostly just want the case.  The Meade 4000 series is parfocal, but I don't think the eyerelief is constant.

 

I think I might have something figured out here though.  At 1250 mm and f/10 (I don't plan on getting the reducer), the only times I will not be using a Barlow would be for full-disc Solar/Lunar observing, and maybe for globular clusters (it's not much of a wide-field 'scope---I will probably get a refractor for that).  If I wanted to add a Barlow, an 8% error could be pretty significant I think.  So what I would need to do is add the Barlow, rebalance the OTA, and realign the telescope for the new center of mass.  The way I read how to do that is to place the telescope at home on top of a pencil to balance it and find the center of mass, then mark the dovetail where that point is.  If I have two configurations I want to use (with and without a Barlow), then I would need to make two marks.  Not sure how difficult it will be in the dark and in the cold though, to find the mark to rebalance the OTA.  With a StarSense, realigning the telescope should be a breeze though.  I read also that realigning the telescope every hour or two will also improve tracking performance on the budget mounts, which StarSense makes easy to do.


Edited by Nicole Sharp, 26 November 2018 - 01:02 PM.



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