2" EP in a 1.25" PowerMate? (and other questions)

[jeffbiehle]

Hello Australia! Greetings from Up Over (Austin, Texas). I was doing some searching of eyepiece reviews and found this web site. Great discussions you guys have here (although I may not be able to understand some of the constellations/sights/etc. that y'all experience and/or talk about)!

I have preliminary spousal approval ;) to spend some coin on some good eyepieces. I've been looking at the Meade 5000 UWA's. A bit much for my budget but I might be able to swing it. Meade is offering a set of UWA's with a nice-looking brushed aluminum case. The set contains a 6.7mm (1.25"), 18mm (1.25"), and a 30mm (2") for US$749 (case included). Retail of the eyepieces separately would be about $930, so it's a nice little discount. Was thinking if I got this I would also consider getting a TV 2.5x PowerMate (1.25"), but didn't know if the 2" 30mm UWA would fit in it well. Apart from the 30mm being a monster (I've heard nearly 4 pounds/1.8 kilos???), are there nice adapters that would allow it to fit into the Powermate, and would I lose anything in the "translation"? (since it's a 2" going into a 1.25" barrel)

Does anyone have any experience doing this? Would appreciate any and all info/suggestions/ridicule/etc.

Thanks!
Jeff

[ving]

hiya jeff, and welcome to the forum.
the short answer to your problem is the if you want to barlow a 2" EP you need a 2" barlow. 2" barlows usually have 1.25" adapters so you could use your smaller EPs in your 2" barlow. As far as i know you cant get an adapter for a barlow that allows you to go up in size, only down.

:hi:

[davidpretorius]

Hi and welcome Jeff

what is your scope?
what ep's have you got already?
what do you prefer looking at the most ie planetary / wide field?

My immediate reaction is not to try and fit your viewing habits to a given set.

The powermate range are great and they are keepers. They should be there in 5 years time when you buy your first pentax or panoptic etc.

There are some great guys here to match your scope with the ep range to suit your budget.

[janoskiss]

Welcome Jeff!

Have you seen a 30mm 5000 UWA in the flesh? It's enormous!! :eyepop:

No, 2" EPs won't work with 1.25" barlows: the light from the 2" EP is "too big" to fit through the 1.25" barrel of the barlow. btw Strange selection of EPs in that kit. Big gap between the 18 and 6.7mm. :shrug:

[norm]

Welcome Jeff to the forum :welcome:

[jeffbiehle]

Hey gang, thanks for the warm welcome and speedy replies! I like you guys already :D

I had suspected as much re: the 2" fitting in a 1.25", but thought it would be worth the ask. I'm still a newbie at all this stuff, and would prefer not to make mistakes with my bank account.

David, per your questions, I have the following equipment:

- Orion XT10 IntelliScope (10" dob)
- 10mm and 25mm Sirius Plössl
- 5mm Orion Stratus (68-degree)
- 3x Meade Barlow

I've only had this for about 8 months. I also have a Meade 4400 (4.5" reflector) that I rarely used. After a trip to Space Center Houston a year ago (which I highly recommend if you ever come Stateside), I was inspired and invigorated to study the night skies more diligently.

At the moment I prefer to look at all things heavenly, although we've had some amazingly clear mag 4 skies lately and I've been astounded at the wealth of galaxies I've been able to see. My current favorite is the Sombrero, which has a very distinct core. But I love looking at the planets, especially Jupiter, and the moon as well. The Stratus is my only wide-angle, and I must say I am underwhelmed by its performance. The views are not very clear--I get as good or better views with my 10mm barlowed. I may get rid of it

My interest in the 30mm UWA is my desire to coax some more detail out of the galaxies and fit more "stuff" into the view. Right now they're your basic smudges--want to get to detecting hints of spirals, dust lanes, etc., if possible.

And janoskiss, you're right, it is a pretty big gap, but I'm sure it's intentional so you can fit in other UWA's in the range as time (and money) permit.

Thanks again for the help!

[davidpretorius]

based on your f5 scope, i would be very particuliar on what eyepiece.

I would do a search for username ausastronomer , what he does not know is not worth knowing.

Basically there would be a thread recommending a good range of ep's and also the best top end eyepieces as well.

[ausastronomer]

Hi Jeff,

As a couple of the other guys mentioned your scope can be very finicky on what eyepieces it digests. It is actually an F4.7 scope not F5 like the Guan Sheng (GS) version. The Orion scope being of Synta manufacture, has a 10" (254mm) primary with a 1200mm focal length. The GS version uses a 250mm primary with a 1250mm focal length which at F5 is slightly more forgiving on eyepieces and also shows a little less visible coma, but the differences are marginal and wouldn't even be noticeable to a lot of people.

However, you do need to use the right eyepieces in such a fast scope.

The Meade kit you mention is a good starter point but with those focal lengths their is no need for a 2.5X Powermate (best barlow money can buy). You can't use the 2" 30mm with the 1.25" Powermate and the 18mm in the Powermate gives 7.2mm which is pretty close to the 6.7mm so it "doubles up".

The Orion Stratus eyepiece you have represents very good value for money. If you can't afford the absolute best (Nagler ot Pentax XW) the Orion Stratus are a very good alternative at a very reasonable price. At F4.7 they will soften marginally at the EOF but they are still light years ahead of anything else that is similarly priced. IMO they offer 90% of the performance of the premium widefields at a fraction of the price.

I would give serious thought to the following options:-

5mm Stratus (already owned)
8mm Stratus
13mm Status
30mm Stratus 2" eyepiece.

This will cost you less than your proposal and gives you lots of observing options with good image quality.

I would also consider selling the other accessories you own apart from the 5mm Stratus. Any optical system is only as good as its weakest component. There is no point having "some" good stuff and some not so good stuff. The not so good stuff just never gets used when you realise how poorly it performs compared to good quality accessories. The optical quality of the scope is sufficiently high to justify good quality eyepieces.

CS-John B

[jeffbiehle]

Hi John. Thanks VERY much for the comprehensive suggestions. I have also been strongly considering the 30mm Stratus 2" (on back-order from Orion until July :(). As I had mentioned, to date I've been dissatisfied with the 5mm Stratus. I don't know if it's something I'm doing wrong with it, but my SP's provide a clearer view (granted, they're lower mag, but still. . .). When I pop in the Stratus and look at Jupiter, for instance, it's not sharp. Bright flare coming from the planet, bands are fuzzy, etc. On Saturn I can't really make out the Cassini division, and that would seem to be a prerequisite, eh? Maybe I just have a dog ep? Or is it something internal that needs to be cleaned? I'm an eyepiece-moron so I really don't know. Any thoughts you might have on this?

Thanks again!
Jeff

[janoskiss]

I'm almost certain that there is not "but still", and what you are seeing is wholly a consequence of magnification. :) Going from a 10mm to a 5mm makes a huge difference in how the image will look. Only under exceptional conditions will you get a sharp image with a 5mm (240x), but you will with a 10mm (120x) even under ordinary conditions. btw I read on CN that the short FL Hyperions (Stratus' alter ego) are on special in the US.

[davidpretorius]

Jeff.

I would try and get a fell on the "seeing", ie how much is the atmosphere moving, before you blame any tools. I have a 5mm lv vixen and if i tried to view jupiter at 30 degree only (i assume it is low on the horizon for you), then on clear nights, i would give myself a 1/5 chance of resolving much at all. Whereas Saturn will be a little higher and the cassini division should be a little easier to resolve.

So it comes down to seeing

http://damianpeach.com/simulation.htm
http://damianpeach.com/pickering.htm

as good a collimation of your scope as possible

easy article
http://www.schlatter.org/Dad/Astronomy/collimate.htm
more involved
http://legault.club.fr/collim.html

and cooling of scope
get your self a thermometer, take it outside and wait till the temperature stops dropping, then wait 1/2 hour for your main mirror to catch up.

if you can get your head around collimating and then spending as much time as you can observing the conditions to be able to rate the "seeing", then you know if you are able to use a 5mm or a 4mm.

These three areas are critical when using the higher magnifications.

ps, By the way, that ausastronomer knows his stuff, he is our go to man when the questions get tough!!

[jeffbiehle]

Thanks David and Steve (and John). You guys are all awesome!:bowdown:

Seriously, I'm fairly new at this stuff and realize how much I need to learn. I collimated mine recently, but maybe I need to be more diligent in it, and it's possible it's not as good as it should be. I will also try your other advice David.

John, I'm going to seriously consider your Stratus suggestions. Until about 6 weeks ago all the 1.25" Stratus' were on sale here for US $95. They've since gone back up to US $120, but I think they were blowing out inventory--does anyone know if they switched manufacturers lately? I also think the 8mm used to be a 7.5mm. Any-hoo, I'll try to maintain patience here. I am anxious to check out their 30mm.

Will keep y'all posted.

Thanks!
Jeff

[davidpretorius]

its the aussie spirit!!!

don't try and digest all at once. I am a fanatic and i feel it took 6 months of almost constant viewing for me to get collimation to a level where i am comfortable to tweak it during the night.

And i still have trouble predicting from naked eye, what the avi's of jupiter will be before i start imaging jupiter at 1600x.

I spose like everything else, it takes time and patience for the gaining of wisdom and experience.

It's a great hobby

[jeffbiehle]

Yes, INCREDIBLE hobby. Amazing how exciting it can be. I know I'll continue to sink more money into it, but hey, it's worth it!

[ausastronomer]

Jeff,

Can I suggest you buy 1 Stratus for starters, say the 8mm and then see what you think of them. As the others have said the 5mm in your scope gives 240X which will give poor image quality unless the atmospheric conditions (seeing) is very good. The 8mm will give 150X in your scope which should hold up OK in fair to better than fair conditions.

CS-John B