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Old 31-05-2018, 06:40 PM
Nothingman (John)
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Barlow wrong size for scope

Hey all,

New here, bought my first scope a few weeks back. Skywatcher Heritage 103p with the eyepieces that come with it. 25mm & 10mm.
The guy at ozscopes talked me into buying a SkyWatcher 2x(D) 1.25" Single Barlow Lens.
He also threw in a ex display 4mm eyepiece...

Anyway. I had heaps of trouble getting the Barlow to focus. I finally worked out if I took the focuser off and held the eyepiece in further information could get focus. (The eyepiece tube is too long) Or if I shortened the focal length of the scope. However after doing so it didn't look much better than looking through thee original eyepieces or the 4mm.

Having done some research now the Barlow seems like it isn't necessary for the scope and eyepieces I have.
I plan on returning it.
What should I replace it with. The 4mm ex display isn't the best viewing. It's a fair bit darker and a bit blurry. Also very short eye relief makes it difficult to use.
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  #2  
Old 01-06-2018, 07:57 AM
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multiweb (Marc)
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When you barlow a scope if anything you would have an in focus issue as you need to push the barlow further down the focuser to reach focus with an eyepiece or camera. So if you can reach focus with an eyepiece you should be ok to focus with a barlow.
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Old 01-06-2018, 12:14 PM
brian nordstrom (As avatar)
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Yes , I agree with Marc the eyepieces should reach focus , except the 4mm yikes !! a 2mm , I would not bother as even TelVue don't go there .

I would return the barlow and get a 15mm eyepiece instead .

Brian.
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Old 06-06-2018, 09:00 AM
Nothingman (John)
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Yeah I am planning on returning the Barlow.
My scope came with a 25mm and a 10mm EP.

What should I go for as a replacement?
I wouldn't mind a better view of the planets and some DSOs.
At the moment I can see Jupiters bands and moons. Saturn and rings.
But Mars appears as just a bright red star.

With my current EPs I'm having trouble finding some DSO objects.
Spend a couple of hours last night looking for the southern pinwheel and the sombrero galaxies with no luck.

According to all acounts my scope should be able to see most of the messier objects.
Is it the eyepieces holding me back? Or more likely viewing conditions, light pollution. Etc?

Thanks
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Old 06-06-2018, 12:08 PM
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Suzy
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Hi John,
As Brian said, go for the 15mm eyepiece. A wideview one, even better!

I have a 4" dob and that's my most used and then I whack on the 10mm for planets.

The Andromeda galaxy shows up very well as does the Orion and Carina nebula. Take a tour around the area of the Southern Cross, there's a lot there to keep you entertained. You can view the brighter Messier objects such as the Lagoon nebula, some globs, I'd be surprised if you can see most of the Messiers tho . Light pollution is a killer and there's a number of galaxies on that Messier list that I can't see with my 10" from home.
With the Sombrero galaxy, I struggled with my 6" and was only just able to make it out (from both home and a dark site). For galaxy viewing that's typically a nice bright one (awesome views in my 10"). So for my 4", I mostly stick to objects that are observable thru binoculars. Great for star cluster viewing. I have done a number of threads here on bino & small scope observing, maybe do a search?

I had a lot of fun touring Canis Major with my 4", so many gorgeous golden coloured stars. Point it to Wezzen and go for a tour around. VY Canis Majoris is easily nabbed, closeby is the Mexican Jumping Bean cluster and a nice colourful double.

As for the Pinwheel galaxy, good luck with that , thru my 10" dob in light pollution it took me 6 months to find. I had to reach for extreme measures by using a large deep sky map with intense star hopping . When I eventually found it, it was very obvious why it took me so long & I wish I hadn't wasted my time, I observed nothing else in that time as I was on a mission, but oh well, ticked that off my list. All that could be seen was the core, so it just looked like a star and only a hint if you looked hard enough of some nebulosity just around the core.
I then saw it thru a 16" dob from a dark sky, I still wasn't impressed though .

Don't wait for objects to get too low, the murk in the lower atmosphere can muck with the views. About 30 degrees up I find is good.

For serious deep sky observing, a minimum of 8" aperture is generally recommended. Meanwhile, there's still a lot you can do with that 5".
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Old 06-06-2018, 12:54 PM
Nothingman (John)
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Ok, thanks heaps Suzy, lots of good info.

You still recommend going with a 15mm when i have a 25 and a 10 ?

Something along these lines?
https://www.ozscopes.com.au/skywatch...-eyepiece.html

Good to know I’m wasting my time with some of the galaxies, i will definitely check out your posts on small scope observing.

Will i get a better view of mars with my scope? Or is a bright star the best ill get?

Pretty good feeling when you do find a certain object, or you do start to recognise constellations, Scorpius blew me away when i realised it was right in front of me, and the size of it!

Never realised I would have this much fun observing
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Old 06-06-2018, 05:56 PM
brian nordstrom (As avatar)
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Yes that 15mm is a good one , but also take a look at the ' SuperViews 'from either Andrews or Bintel , these are still the best eyepieces for the price bar none .

I have personally tested a SV 15mm against my 15mm TelVue Panoptic ( a rare eyepiece ) , the 20mm SV against my 19mm Panoptic and the 30mm SV against my 27mm Panoptic and you would never think that these SV's are 1/10th the price of the TelVue's.
These 3 are 1/2 the price of one Panoptic .

These perform to an easy 90%of the much more expensive eyepieces and at 68* they have a nice field of view .

Highly recommended .

Brian .

ps. I only grabbed the 3 SV's mentioned here 2nd hand from the classified's here to do a side by side in all my scopes with the TelVue's and I was very impressed , since sold sadly tho .

Quote:
Originally Posted by Nothingman View Post
Ok, thanks heaps Suzy, lots of good info.

You still recommend going with a 15mm when i have a 25 and a 10 ?

Something along these lines?
https://www.ozscopes.com.au/skywatch...-eyepiece.html

Good to know I’m wasting my time with some of the galaxies, i will definitely check out your posts on small scope observing.

Will i get a better view of mars with my scope? Or is a bright star the best ill get?

Pretty good feeling when you do find a certain object, or you do start to recognise constellations, Scorpius blew me away when i realised it was right in front of me, and the size of it!

Never realised I would have this much fun observing
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Old 06-06-2018, 06:12 PM
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My pleasure John .


I can't recall what Mars looked like in my smaller scopes but you should be able to make out a reddish disk and perhaps some dark shading. You mentioned earlier that you see it as a bright red star... it shouldn't resemble a star (point of light), but more disk like . I hope you're not confusing it with the bright red star, Antares in Scorpius . Mars rises around 9pm at the moment. But there's a large dust storm happening at the moment and it may even go global, so I'm really not sure what view you'll get at the moment. You picked a good time to get a scope because Mars is heading for opposition on July 27th, then August 1st it'll be closest to Earth. It will be the biggest and brightest since 2003, and not get this close to us again until 2035.

If you head over to our facebook page, you'll see a pic I posted this evening showing the dust storm and a comparison view without.

Regarding the 15mm eyepiece, yes, get one despite having the 10mm and 25mm. Across my 4", 6" and 10" scopes, it's been a hard worker on all of them. I haven't tried out a Skywatcher eyepiece but the specs look good and the price is reasonable.

When selecting objects, select ones to about magnitude +6 or +7 and I think you'll have a good chance of nabbing them. Can try +8 as well. Lots in Scorpius and Sagittarius you can get incl. M22, M17, M7 & M7.
Oh and I forgot to mention earlier, The Tarantula nebula in the LMC- you'll see that also.

Here's one of the articles I did, you should be able to get lots on here, but maybe not the galaxies (have a go anyway). Don't observe when the Moon is out, it'll dim down those faint fuzzies. Planetary viewing is no problem. Highlights of the Winter Sky

And I did a search for some of my obs, here's the link for the search results: http://www.iceinspace.com.au/forum/s...archid=4347831

Last edited by Suzy; 06-06-2018 at 06:22 PM.
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Old 07-06-2018, 04:26 AM
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gaa_ian (Ian)
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Good advice to John Susy
That scope is one of our best sellers but is at its best as a wide field scope.
John if you want the higher powered views of the planets a prime Eyepiece of 5 or 6mm will serve you better. But it needs to be a long Eye relief wide field eyepiece, a plossol of that size is like looking down a popper straw !
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Old 07-06-2018, 11:18 AM
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It looks like you're up for two eyepieces, we love to spend peoples money .

On October 18th for a short time after sunset, all the planets will be visible at the same time, stretching across the entire sky from east to west. Something to look forward to .

Brian, that's awesome information on the superviews. I wouldn't mind a cheapy 5mm secondhand one (one day) for my 4" as the kids love to use it for planets. My Pentax XW 5mm weighs nearly a kg so a bit heavy for it, plus it's not for kids use.

Hi Ian ,
I love to spend summer nights sitting on a blanket on the grass with that size scope. I'm so comfy and no setting up! And the kids are easily able to track planets themselves, having the red dot finder makes it even easier for them to find objects. I did an extensive obs session with Canis Major and did a report comparing the views through the 10" and the 4", great fun!

Personally, for DSO observing, I prefer the 15mm on the 4". It hits the sweet spot nicely. The view isn't too magnified and dark from high power and not wide enough that I feel like I'm looking through binoculars. I find it great for actual 'observing" an object. The eyepiece I use and love on it as Orion Expanse 66 degree field of view (fov), so yes, go the wideview!
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Old 08-06-2018, 10:45 AM
Nothingman (John)
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Thanks guys,

Have returned the barlow and swapped it out for a skywatcher 6mm wide angle 66 aFOV.
I am lso going to order a 15mm from either Bintel or Andrews as advised.

figured it would be better to have more options than less

I can see what you mean, as when i look through the 25mm I get a much clearer (brighter) view than the 10mm. and the 4mm I got thrown in, is very dull and quite hazy. And is like just like looking down a straw

Only got a brief view with the 6mm, between clouds last night, but the view was much clearer, although still a bit darker than the 10mm.


Really looking forward to the 15mm, sounds like it will definately be the go to eyepiece. thanks for all the sound advice!

Quote:
Originally Posted by Suzy View Post
You mentioned earlier that you see it as a bright red star
As for mars, yes it was definitely Mars, although it was around 10pm, so still relatively low in the sky, hard to describe, but didnt look exactly like a star, it was quite bright and hard to make out any detail.
Anyway, i will spend some more time on it in the next few weeks and let you know how i go!
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Old 08-06-2018, 01:30 PM
brian nordstrom (As avatar)
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Good move John , just one more thing , don't expect to see to much detail the first few times you view the planets as it's like training , training your eye and brain to ' See ' takes time as the details are tiny and good views are fleeting as the atmosphere changes .
But its neat how the eye/brain learn to show you more over time .

You will really like the SV 15mm an awesome eyepiece .

Brian.
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Old 08-06-2018, 03:43 PM
astro744
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You will love the 15mm as it is a great eyepiece for general low-mid power observing on your 'scope but it won't do much for Mars as the power is too low for this small planet which is currently about one third Jupiter size but will increase to just over half soon. The 6mm will be better and yes the image will be dimmer as the exit pupil is smaller but still quite sufficient at 1.2mm. In fact get a quality 2x Barlow and at 0.6mm exit will be about you limit at a power of 216x. I would drop to a 4mm eyepiece for 162x and 0.8mm exit pupil or 5mm for 130x and 1mm exit pupil, (can use Barlow to achieve those focal lengths). The exit pupi is an indication of brightness.

Telescope focal length, f.l. = 650mm
Telescope aperture, d = 130mm
Telescope focal ratio, f.r = f.l./d = 5
Magnification = Telescope focal length / eyepiece focal length
Exit pupil = aperture / magnification
Exit pupil = eyepiece focal length / telescope focal ratio
Minimum exit pupil usually 0.5mm (determines highest magnification)
Maximum exit pupil usually 7mm (determines lowest magnification)

A quality 3x Barlow will work well with your 15mm eyepiece giving a 5mm. The Bintel 2x and 3x Barlows are quite acceptable and work well. Stay away from the shorty type (vignettes) and also the 5x (chromatic aberration from the Barlow, unless you get a Powermate which will cost as much as the scope; you don't need it).

If you don't want to use Barlows then your other choices are expensive 3,4 & 5mm TeleVue DeLites or TeleVue 6-3mm Nagler zoom. I'm not saying you go out and get these as they'll cost way more than your 'scope and I'm simply trying to show you other options. I don't know how much money people have to spend and I think sometimes better alternatives are welcome suggestions.

My son uses the Bintel 2x & 3x Barlows with the 15mm Superview with great results and I just noticed Bintel have a 2.5x Barlow which would give you a 6mm focal length with your 15mm Superview and it would be much more comfortable than a standard 6mm eyepiece because it would have the eye relief of the 15mm.

Lots to think about there. Whatever you choose, enjoy!
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