Getting clearer views

[REG78]

Just been gazing th last few nights I'm getn pretty decent clear views with just my 10mm & 25mm super wide EPs supplied with my skywatcher 130-900 would I see a difference in views ie much clearer if I wer to upgrade to a few plossls 

[billyharris72]

Hi Reg78. I'm assuming you have the modified achromat eyepieces, which are not bad. I found when I upgraded (to Skywatcher plossls) that there was some improvement, particularly at higher magnifications (though the 25mm was better too). It's a subtle improvement on most things, but the contrast in the plossls is better and there is less glare and reflection on bright objects like the moon. I think this is probably less due to the optics (the MA design is pretty good) than to overall build quality. The plossls are metal construction, which is easier to blacken, which cuts down on internal reflection. It's been a while since I checked but the plossls are probably better corrected at the edges too.

When I upgraded I went for direct replacements for the 10mm and 25mm eyepieces that came with the scope, which with hindsight was probably not the cleverest. Best to go for some other focal lengths; the 10 and 25mm can be replaced later. I would definitely recommend a 32mm plossl - this will give really bright views and the widest field of view that your scope can attain. Of the MAs, the 10mm is considered weaker (possibly because it is used more often on brighter targets) and that may also be worth replacing, though you might want to go for something between 8 and 12mm.

Astroboot almost always has decent quality plossls (Revelation, GSO etc) going for around the £15 mark if you wanted to get started for minimum outlay. Also, do you have a Barlow? A decent 2x Barlow lens can be picked up for under £30 and will effectively double your eyepiece collection.

Billy.

[REG78]

Cheers bill bit of good info ther yea have th Barlow tht came with th scope but isn't up 2 much it's made of plastic don't really use it because of this I'm gona up grade soon 

[laudropb]

If you are happy with your supplied eye pieces I would not be in a hurry to change them. Gain experience with what you have first then you will be better able to decide what you need most. If you are desperate to spend your money I would consider a 6 mm ep. That would give you a magnification of 150 x. Very useful for lunar and planetary observing.

[REG78]

1 hour ago, REG78 said:

 

Cheers for tht was just wondering was ther much difference in clarity in up grading to plossls

[laudropb]

I do not think you would see a massive difference in clarity. I was think along the lines that you might want a wider FOV than you will get with plossls.

[REG78]

What would you recommend 

[Alan64]

Have you installed the motor yet, on the RA axis?  That would help in stabilising the images, especially at the higher magnifications.  You can also eliminate the dreaded battery-pack with a 240V AC to 6V DC power adaptor, rated from 1.5 to 2 A, and perhaps with a 5mm OD plug with a positive(+) center-tip.

Here's a 6mm with a wider field-of-view and a large eye-lens with which to look through... http://www.365astronomy.com/6mm-The-Planetary-Eyepiece.html

You also have the option of a 12mm(75x) along with a 2x barlow, and for a simulated 6mm(150x).  Then, in future, combine an 8mm(113x) wide-field ocular with the 2x barlow for a simulated 4mm(225x).

[REG78]

No Alan haven't got rnd to using it yet,was actually thinking tht myself about th higher magnification EPs goin for a wider fov have you got any of thm would you recommend thm instead of high mag plossls

[kev100]

Hiya, I used to have that same scope, and I found a set of Revelation plossls (9, 20 & 32mm) made a massive difference to the view. Much sharper, clearer and more contrasty than the standard items. FOC isn't the best, but for the price I think they were excellent in the 130/900. I also found that 9mm was pretty much the shortest focal length I could use in the scope and still get sharp views (I tried a fixed FL 7mm Ep and it was terrible). Barlowing was poor, too. Of course there are better EPs, with wider FOVs, and if your budget will stretch than you should definitely explore the option. However, the Revelations do pack a lot of bang for your buck in a scope like yours.

 

Kev

[REG78]

Cheers kev for th info was thinking of 6mm wide fov what do yo think in my scope would it be fine

[kev100]

Hiya, I guess it depends on the eyepiece, but I would have thought 6mm focal length (giving x150mm) in your scope would be too much. Like I mentioned, I tried a 7mm plossl in mine and and the view was very dark, and the field of view very narrow (meaning I had to move the scope a lot to keep track of the object). If I remember rightly, I was trying to keep track of Jupiter and it was really disappointing - the view was very dark, the planet 'soft' and keeping sight of it was a pain.

If your budget will take it, a 68-degree EP, or an 82-degree (Meade, Explore Scientific, Vixen, etc) one will give a wider field of view, allowing you to view the object in a more leisurely fashion (and you'll see more of larger objects), but I still wouldn't go much beyond 9mm (7-8mm, depending on the EP, but no shorter). BST Starguiders are another well favoured option.

Whilst the Revelations/plossls were a revelation (pun alert) in terms of sharpness/contrast, etc, I soon found that they were lacking in terms of field of view, and I set about getting wider FOV EPs when I upgraded the scope.

Like others have already said, don't be in too much of a hurry to upgrade your EPs. See if you can try some different ones (at a local club/star party/friends) first. You may decide to upgrade the scope first, and then find that those you get now for the 130/900 aren't suitable ...

Kev.

[kev100]

By the way, a simple rule of thumb for checking what the maximum magnification a Newtonian will deliver and still be sharp is to look at the diameter. In the case of your 130mm scope, if we take 130 times mag as the max, then 900 (scope focal length) divided by 7mm (EP focal length) equals 128.5. I'd say this would be the maximum such a scope can deliver and still be sharp and clear. Any higher magnification will likely be disappointing in terms of sharpness/clarity (depending on the EP, of course).

Kev.

[billyharris72]

Depends on the object you're observing, but I would think a 130mm could support 150x without too much difficulty for lunar and planetary viewing and splitting double stars. Would not be my first choice on the majority of DSOs, but it would not be a bad addition by any means. I've used a 4mm plossl on my 130P (f5, so gives x162.5) and works well for planets. You should get something similar with a 6mm in yours, but with slightly better eye relief.

That said, I notice your original post suggests you like the views with the eyepieces you have. One good piece of advice I've picked up from this forum is that it's often best to sit tight until you find the kit you have is starting to hold you back. That way you don't spend more than you need to, and when you do spend it will be on the right stuff.