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New telescope and eyepieces

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I'm replacing a cheap 1990's scope with a nice new scope and equatorial mount.  I've done a lot of research but I really want to double check to make sure it will work for how I intend to use it before I buy.  Everything seems to be on sale now, which is awesome.  I want to look planets, nebulae, deep space objects such as galaxies and globular clusters  and maybe even planet nine (dreaming on that one, I know :) ).  I want to take long exposure photos with nice colors.   I'm at about 45 degrees north, and 850 feet above sea level, fairly close to a major city but planning to take the scope into the countryside.  It would be nice to do some viewing from the yard too.  

Here's what I've got so far.  Does anything here make anything that I want to do above impossible?  For example, is a 127mm scope large enough to view planets, or will that never happen?  I've seen some nice pictures from the scope on astrobin, but I can't tell how much they've been processed or if they were from up on a mountain.  Are there any known defects with the items I've selected?

Mount:  Sky-Watcher EQ6 from Skywatcher
Scope:   Explore Scientific 127mm aperture, 952mm length (aluminum triple pane)
Add ons: 
   2 inch barrel to replace the 1.25 inch that comes with it.  Explore Scientific
   Field Flattener (for astrophotography):  Explore Scientific 2" FIELD FLATTENER - FFEDAPO-00 
   Imaging camera: Sony A65 DSLR (already own)
   Finder scope: Solomark F50 50mm Guidescope 190mm Focal Length, F/3.4 Focal Ratio, Fully Coated w/ Helical Focuser
   Guiding camera: TBD - maybe I can go without to start??
   Eyepieces - TBD - open to suggestions.  Looking for good quality 50, 100, 150, and 200 magnification as wide as I can afford or is worth the extra cost.  Are the Explore Scientific pieces good?
   Power supply -  TBD - open to suggestion
   Light pollution filter for imaging camera - going without it for now and seeing how it goes in city vs out of city
   Dew buster:  going without it for now
   Carrying case:  Going without for now

    Is the difference between a 52 degree eyepiece and a 100 degree eyepiece noticeable on everything or not at all (moon, galaxies, etc?)?  Do I want to a mix of narrower on the moon and planets and wider on deep space?  

    Are there limitations on smaller scopes that set a cap on true field of view, for example, maybe a 127mm aperture scope can't get a 3 degree field of view with a 2 inch barrel? 

    Do I need 3 degrees true field of view to truly see all of Andromeda through an eye piece?

    Is there a good site showing how many degrees deep sky objects take?  For example, I've read the moon is 0.52 degrees and Andromeda is 3 degrees.  I think Jupiter is 0.07 degrees, but that was something I calculated so it might be wrong.   

    When is eye piece waterproofing important?  Is it for rain and dew?

    I read if you are over 45, then you should avoid eye pieces over 5 times the focal ratio (37.5mm for this setup).  I'm close, but not quite there so I can't test this theory.  Is this true?    

    Fun fact - one book I've been reading has a section on eye pieces to avoid, and they have a photo of my current eye pieces from the 1990s scope.  

   Barlow/Focal extender:
     I have some barlows from my 1990s scope set.  It seemed to work ok when zooming in on the moon.  Is that something I should upgrade, or are they all the same quality?  Should I skip the 200 magnification eye piece and get a new barlow instead?

Power supply:
  I've read some power supplies may harm the batteries of your equipment (car battery chargers was the example given of a potentially bad one).   Does anyone have a recommendation of a good power supply they've used for a while and where I could find it?  

Thank you!


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Hi, monetrum, and welcome to SGL.

1 hour ago, monetrun said:

I want to take long exposure photos with nice colors.

I would make this your first purchase, it could save you a fortune in the end. The AP will have the most critical requirements, so build you setup with that in mind and the visual will be "easy" (relative term!).

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Ah that is a good shift in strategy.  I like it! 

I just saw a band on Jupiter for the first time tonight using the old 60mm aperture and 800 length scope.  I could see a band using a 12.5mm eye piece, which is only 64 magnification.  I thought I would need much higher to see Jupiter.  Couldn't get any closer without losing Jupiter.  4mm is the next eyepiece I have, which jumps to 200 magnification.  I guess 64 to 200 is too big of a gap between eye pieces so I get lost in the sky between them.  

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Hi monetrun,

In the equipment list you own, the Sony A65 many not be ideal for deep sky astrophotography as its translucent mirror technology splits up the light coming in between the viewfinder and image sensor, so you would need longer exposures with the associated complications than when using a DSLR with a flip mirror. You can still get reasonable images though (I have used the similar A58).

There is definitely a difference between views through a 52 degree and a 100 degree eyepiece. You will get a much wider true field of view through the latter and the visual experience will probably be more pleasant. The wider view eyepiece would also probably have a higher eyepoint making viewing more comfortable. Your true field of view will depend more on the focal length of your scope rather than the aperture. With your scope you should be able to view a full 3 degrees with a 30mm eyepiece with 100 degree apparent field of view (true field of view is the apparent field of view of your eyepiece divided by the magnification)

Regarding the 45 year age, I think it might be in reference to the diameter of the exit pupil which can be a maximum of 7mm for humans but decreases with age. You can calculate the diameter of the exit pupil by dividing the aperture of your scope by the magnification. For your scope you will get an exit pupil of 7mm at about 18 times magnification which would be obtained with a 52mm eyepiece. I don't think there are many of these but you should probably not go for a higher focal length than 40mm for your eyepiece. 

Happy Astronomying!

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Wo was that’s some good research!

scope choice and mount seem very workable for everything, yes that scope will have no problem with all those targets including planets, you may find yourself upgrading your camera though in the medium term.

I agree with your auto guiding idea, it’s a discrete add on that can easily be added a later date, not essential to start. Might be worth considering a polemaster or similar to make alignment easier though.

as for the eyepieces - I’ve never seen more than 2 degrees worth of Andromeda. It is big but for visual I find the light levels drop off quickly and my 125mm from an averagely light polluted garden only picks up the central core (but yes it’s really is that big it’s crazy when you think about it!)

i wouldn’t worry about the “if you’re over 45 thing”, peoples eyes are so variable that there really isn’t any point worrying the biology. As a general rule, keep the exit pupil above 0.75mm and below about 5.5mm and most people will be absolutely fine.

the widefield eyepieces are in vogue at the mo - the biggest thing to consider is the limiting field of view of your scope; there’s no point forking out for an eyepiece that gives 4 degrees afov if your scope has a maximum of two degrees. But in all honesty without a really really dark site, the bigger wider stuff by definition is much fainter anyway so harder to see, a good low power Plossl (32mm ish) will show you a huge swathe of the sky anyway, so it’s really one of those “personal preference” things - at the top of this site on the banner is a link to “astronomy tools” that has a field of view calculator which is super useful for these sort of musings!

celestron/skywatcher do a powertank that is quite inexpensive and fairly ubiquitous.


Edited by Mr niall
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Just had another thought - and this is just a personal opinion so feel free to ignore - but that is a frighteningly expensive shopping list. Are you definitely sure you’re going to enjoy all this enough to warrant it? Just a thought.

Edited by Mr niall
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The only bit I can really comment on is the power supply question.


A car battery charger is definitely a bad idea - the modern smart chargers might not supply anything unless they get feedback from a battery, so they're out. The old type (straight rectified transformer type with or without current control) are also no good - the ocv (open circuit voltage) can be as high as 22V+ on 'fast' chargers, which is highly likely to cause electronic arguments and very sad magic pixies almost instantly... They rely on a load to somewhat regulate the voltage. Even trickle chargers can be 14-15V which is right on the spec limit of most equipment (astro or otherwise).


Any specific power tank of the appropriate voltage (6 or more likely 12) will be fine though, or a car battery - or a decent quality FULLY REGULATED mains power supply.


The dedicated power tanks have the bonus of extra features (torches, red light, correct connectors) but a portable jump start unit (not the plug in type) is almost the same, but you'll need to make or source leads etc.

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4 hours ago, Mr niall said:

Just had another thought - and this is just a personal opinion so feel free to ignore - but that is a frighteningly expensive shopping list. Are you definitely sure you’re going to enjoy all this enough to warrant it? Just a thought.

The sales and coupons definitely help, but it is still about double what I thought I would pay going into it.  The eyepiece cost really surprised me.  I justify it by telling myself the mount and scope will have value.  Not sure how often the mount would need repair or what that costs.  I'm hoping it lasts for 20+ years.

We have young kids and young nieces and nephews, so I really want something very easy to use that gives nice views and tracks well with the stars.  Something not too heavy or bulky to carry out to the country (scopes under 50 pounds for example).  I don't mind finding objects myself, but having an mount that stays with object is something that will get me star watching a lot more. 

There is an observatory that has cheap viewing sessions nearby and we saw a globular cluster up close and it was amazing.  The kids also look at a star app every night before bed zooming in on different stars and planets, so I know we will enjoy it.  

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I think you are wanting to do too much too fast. Get a 8 inch Dob and get an idea of what you can see visually before getting into astrophotography. You can get a Dob cheap second hand. As for eyepieces get a 32mm and a 10 mm Plossl and a good barlow and you will have most of the magnification you want. The Dob will last for years with maintenance.

I don't know that much about astrophotography but I do know that deep sky astrophotography costs more than planetary.

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Thanks everyone, I ended up making all the orders tonight  Really excited to use it with family and friends this summer!  I added three eye pieces, all 82 degrees, 6.7mm, 11mm, and 30mm.  

I went with an Orion power supply: https://www.telescope.com/Orion/Orion-Dynamo-Pro-155Wh-ACDCUSB-Lithium-Power-Supply/rc/2160/p/118187.uts?keyword=power supply

I think I just used up the rest of my birthday presents forever :)  

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  • 3 weeks later...

I've had it set up for a few days now.   Last night I showed the kids jupiter and saturn which was really neat.  I also scanned through a few globular clusters.  I realized I needed a little more magnification, so I ordered an Explore scientific  2x focal extender from Amazon.  Right now my magnifications are 30, 87, and 147, so double should give me 174 and 294, so I should be able to see more detail on Jupiter and Saturn. and hopefully I'll be able to see all of M13 globular cluster in focus.  Wow there are so many stars out there when you zoom in on an area. It's insane!  A little surprising that I could see so many in the city.   

At first I just played around with no alignment, then I realized I needed to at least point the mount a little north or the scope wouldn't point in the right direction.  Then I attached the finder scope, which was in better focus than the main scope until I attached  one of the tubes that shipped with it. to extend the length a little bit.  After that, everything was really clear. There were about 40 pages of manual I started to read, but didn't understand and lost interest in with a brand new scope sitting there :) 

I figured out alignment to some extent without reading any of the manual.  I used the 30 mag eyepiece to find a super bright star in the area and center it, so I did three star alignment in the suburb of a main city.  It gave an alignment message telling me my polar alignment was off, which is really helpful, and not surprising considering I didn't really do a polar alignment and skipped so many steps.  It zoomed right to objects for a while, then a little less close, but still nearby after time passed.   I really like being able to press a button to move the scope, rather than loosening and tightening knobs.  

Haven't tried astrophotography yet.  I needed an extra cord to attach the mount to my PC to update the firmware (so the instructions say anyway,) and an attachment to connect the focal extender to my camera (both were around $10).  The mount advertising says it does periodic error correction, so we'll see if that's true, or if I need a scope camera.  I'v read I don't need an eyepiece for astrophotography, which I don't understand at all, but we shall see.  

The power supply works great.  It was only down about 15% after about 6 hours of use.  It charged up to full  - I didn't check the time - it wasn't instant but it wasn't too long either.  I wish I had got one long ago for charging my phone while camping.  

I did not need the 2 inch barrel.  The telescope came with one.  And I probably could have done without the finder scope to start.  I may add the barrel to the finder scope so the scope and finder scope are at the same angle.  The mount is heavy, but I knew that going in.  I can lift the entire setup without the counter weights carry it to the driveway and up/down three steps (legs on tripod not extended)   There's a handle on the mount that makes this possible. 

Edited by monetrun
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Hi monetrun

Would look at a Skywatcher ED80, with EQ6 mount, as can purchase as a package, and takes 1.25mm and 2mm eyepieces with diagonal supplied 

I have mine on an EQ5 mount, and can also get a solar glass filter as well

I use car jump battery box for powering, and have run my EQ5 for a couple of days, with no issues

When do school programs, scout/guide presentation, with club belong to, I use a 17mm wide angle eyepiece

Gives good eye relief with 6-9 yo students, and a wider spread to observe moons around Jupiter

Pic shows my ED80 with solar filter





Skywatcher ED80.jpg

jump start pack.jpg

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