Hyperion 10mm no better than standard SW10- am I doing something wrong?

[Eastridge]

Hi I recently got the Hyperion 10mm + 2 FTR's for plantry viewing as everyone says the 10mm SW suppy with the Skyliner 250 Dob is poor quality. I was aware of the edge astigmatism in a fast scope like mine but decided the good eye relief & flexibility of the FTR's giving numerous lengths outweighed having to keep the planet central by nudging.

Last night compared it (at it's native 10mm) to the SW 10mm and could see no discernable difference. I was stunned as user comments on SGL for this and much lesser EP's implied a real shift in what you could see. We looked at Moon, Jupiter, Mars & Saturn. We stayed up til 2 to ensure best altitiudes, the seeing was rated at 5 by meteoblue and there were no clouds. We always made sure the planet was bang central by frequent nudging. We are in Bideford North Devon

Have I bought the wrong lens for this scope and would I find something else better? Or is there something wrong with our set up that is preventing us from seeing it's true abilitites?

Hubby insists the collumation is fine, but I am wondering if there is something wrong with set up as:

- can't seem to get sharp focus on planets sufficient to see the extent of detail that others say they can with similar set ups

- all planets are giving off refraction - 4 or 6 beams of light radiating from them for quite some distance which I don't recall seeing on our old SW SkayHawk 1145

- occasionally there seems to be a circle of hazy light around some objects even when at best focus we can get.

What do experinced people think, does the above indicate a set up issue?

If there is nothing wrong with set up I think I need to send this back to FLO as it's a waste of c. £100.

[gooseholla]

Did you check the mirrors for dew?

[kniclander]

the hazy circle suggests dew somewhere but in reality the difference between e/ps is usually pretty subtle, it's just when youv'e been doing astro for quite a long time and got used to things a subtle difference can seem like a WOW difference. collimation is very inmportant on that scope too.

[Moonshane]

I presume you are letting the scope cool for maybe an hour before observing? this will make a big difference although you advise you waited a long time so this should not be the issue in your case.

collimation as said above is important.

I have never really used a Hyperion but I understand they are good with all scopes but excel with f6 and slower. my understanding of the fine tuning rings is that they are really designed to 'fine tune' the focal length of the eyepiece to best match your system and then be left alone, not constantly interchanged to create eyepieces if different lengths. I may be wrong about this though.

the diffraction spikes (I'd expect four) are normal and a standard aspect of Newtonians, they seem to increase with aperture too.

it's possible that one reason for your lack of focus is that the primary mirror clips are too tight. they should not touch the primary but be a mm or so off. the design of my home made cell means that the clips are 6-8mm above the primary. all they do is stop the mirror falling up the tube.

don't panic just now and try the eyepiece over a period of time and I bet you'll eventually see the benefits.

[M4lcs67]

I am currently waiting for the delivery of a Hyperion 10mm myself. I finally chose that after brilliant results with my 24mm Hyperion that I bought a few months ago. And incidentally the stock 25mm that came with my scope was the best out of the two (had a 9mm and a 25mm that came with the scope). My stock 9mm was/is rubbish, so ended up not using it (used to use my 24 Hyperion with my 2x barlow to make 12mm). I am therefore expecting big things from my new 10mm when it arrives.

[cs1cjc]

Hi,

Some eyepieces supplied with telescopes are not good, so you might reasonably expect an improvement with a decent eyepiece. I have no experience of a 10mm Hyperion, but from my experience with a 17mm, it should be capable of giving you good views in your telescope.

It sounds as if your telescope was cooled because of the time you spent out, but warmth in the mirror will cause tube currents which distort the image, this is particularly visible with high magnification on Venus, I think.

The radiating spikes are diffraction lines caused by the spider for the secondary and are normal. They can be prominent on planets.

It is easy to check collimation by slightly defocusing on a star at high power and looking for the concentric diffraction circles. See for example:

TMB Website

A circle of hazy light around an object may be due a misty sky or possibly dew on the optics. As a test, you could try using a hair dryer to gently clear any dew from the optics.

I hope this is a help in tracking down the problem.

[Karen]

I think the 10mm ep that came with your 250 dob is a Skywatcher Plossl? If so it will have Super Plossl written on the barrel. These are not the rubbish ep's that peeps on here refer to but the MA ep's that some smaller Skywatcher 'scopes come with.

The Baader Hyperion will give a much wider 68 degree field of view and much better eye relief. The image detail will not necessarily be that much better than with the 10mm plossl.

Make sure the 'scope is cooled and collimated. If you focus on the moon and can see good detail on the craters then there is probably not much wrong. Fuzzy planet images will probably be due to seeing conditions.

I find Mars and Venus to be too bright in a 250 dob so I stop down the aperture.

[michael.h.f.wilkinson]

You may be limited by sky conditions. The hazy ring may be scattering of light on water droplets in the atmosphere (I have seen a lot of that in recent nights). If seeing conditions are below par, no manner of fancy EPs can change that. A few nights ago I could use up to 406x magnification on Mars, yesterday I struggled with 249x (with an outstanding Pentax EP), and even 169x (with a 12mm Nagler) was not that good. If seeing is bad, the best EP cannot save you.

If you want to compare EPs, choose a night of really good seeing to do so.

[Thirdway]

Fuzzy planets = dew on optics. After a few hours viewing in cold and damp conditions I noticed a halo around stars and planets. Getting the scope into some light revealed freezing mist on ever optic surface. Even the scope body had a layer of ice. Just breathing near the EP is enough on colder nights. Thing with EPs is that the differences are not always the ones you were looking for. Also check the mounting of the EP and the 2" adaptor, sometimes you don't get them tight enough when fingers are cold. Collimation quite often alters a bit when the telescope cools and high mag objects can be a problem.

[michael.h.f.wilkinson]

Fuzzy planets can be due to dew (). However Newtonian mirrors in closed tubes do not dew very readily (unlike my SCT's corrector plate). Dew could settle on the EP, but I have not had that problem often.

[twotter]

I also think the SW 10mm plossl gets a lot of bad press on here, even though it's quite capable of giving a decent view of the night sky. It doesn't matter how good your 10mm eyepiece is, or what brand, if the viewing conditions aren't good enough then none of them will give you a good view.

Last night I was viewing Mars and found it to be very fuzzy, despite a cooled and collimated telescope. My 17mm Hyperion gave me the best view but that's down to the viewing conditions.

I do tend to use my FTRs to change focal lengths a number of times during a session. Can't see the point of sticking with one focal length when I've got the option of four available at the twist of the wrist

[dark knight]

Hmmm, I thought/was led to believe Hyperions weren't suitable in fast scopes f/5 and faster

[John]

Nothing particuarly bad about the Skywatcher Plossls, 10mm included. The ones that get the bad rap are the 10mm modified achromat types that are often standard issue with scopes.

In a fast scope like an F/4.7 (the 250PX is F/4.7) you may well not see much or any difference between a Hyperion 10mm and a decent 10mm plossl. The outer parts of the Hyperion field of view will be affected by astigmatism and the central or on axis part of the field of view of most eyepieces is quite sharp and contrasty.

Give the Hyperion a few more chances under different conditions though - you really can't judge from just one outing.

[Capricorn]

Do always try to say that the 10mm is generally poor, doen't mean that everyone is.

The performance is how well the 2 lens (plossl) operate together and by simple chance some eyepieces will have 2 lens that happen to work well as a pair and so give good results.

Catch is it may be say 5 in 100. It also depends on what the observer expects and I suppose that an eyepiece that is comfortable to use will win out over one that may be optically better but not as comfortable.

All eyepiece are somewhat subjective. I suspect that a Hyperion is one eyepiece that some like and others don't.

[spaceboy]

I have noticed a trend with EP's with large eye lens. You have to take into consideration the hyperion's are a decent lump of glass. My theory is if you have a cold ep with a large lens and you put your toasty eye ball up to it you will get a degree of misting on or between the eye lens. This will give you fuzzy planets or frosted effect effect to bright objects. There is also warm EP's that will show a small amount of turbulence to an image similar to a mirror that has not been allowed to cool correctly. This is not so much an issue for plossls as they have small eye lens and less optics inside them.

[Eastridge]

Thanks folks a lot to check and reassuring.

The seeing might well be the culprit as whilst I understand the theory the practical application can confuse me. Does it correspond with 'ground level' visibility as you can see in the day & as BBC include on their weather forecast?

For example, last night meteoblue and weatherweb forecast good seeing so I assumed that it was that, the day and night were cloudless and moon wasn't shimering with atmosphere to any distracting extent.

BUT thinking back whilst the BBC weather site had the visibility as good I couldn't see much into the distance during the day / early evening due to 'haze.' Certainly that afternoon at the coast (c. 5 miles away) I couldn't see Lundy island (c. 10 miles away) at all when you usually can.

Should I ignore 'seeing' forecasts and go with what I can / can't see at ground level or can it be poor visibility at ground level but still OK up into the sky?

[Thirdway]

You don't know until you get your scope out. Even in clear skies there can be atmospheric turbulence which isn't obvious until the magnification increases. This is one reason planets can be difficult because there is an obvious tendency to use high mag, back off to low mag and the image becomes crisper and has more contrast. Anything low on the horizon can be very problematic, even when the sky is perfect. Heat hazes can really mess things up, so can mist and air pollution from dust pulled up from the desert regions.

[Mr Spock]

I have an old Skywatcher 10mm silver top Plössl lying around somewhere. I remember it as being quite good despite what everyone says.