Why Can't I Get A Sharp Image?

[Jimmy Stix]

Hey folks!

I was wondering if you could help me with some questions about my new Skymax-127 GOTO.

After endless nights of waiting I finally managed about 30 mins in my back yard with the scope last night and managed to look at 1 or 2 things. Using the 25mm eyepiece I managed the "brightest star" alignment with Cappella & Vega but I could not get the images very sharp.

Is this because of the atmospherics, not enough cool down (30 mins at most possibly), my limited experience or that stars are just "like that"? I guess you are going to tell that it's probably a combination of all of them but I just wanted your opinion.

Am I expecting too much when looking at stars? I understand the distances we are talking about and the higher magnification but having gotten fairly crisp views through by bins I was a little disappointed that I could not get what I thought was a satisfactory view. Even a quick look at Jupiter and it seemed a little fuzzy. I am so used to almost "razor" sharp images through my birdwatching experiences over the years.

I know I have lots and lots to learn and I am not put off but feel a little down about my first "real" go with my scope.

Regards

Jimmy.

[lukebl]

I don't have a Mak myself, but I understand that they need a good cool-down period before use. 30 minutes is certainly not sufficient.

Also, stars will never appear as anything other than a dot whatever the magnification. They are a long way off!

[bombassa]

Hi

Congrats on your new setup. Hope you'll get some good experiences with it as well.

I don't have the scope in question but can tell that stars should be pinpoint. Sometimes supplied eyepieces are of limited quality and can have problems with the image near the edge but stars near the center of your field of view should nevertheless be sharp. Jupiter should likewise be sharply defined.

Try letting it cool down for longer perhaps. I know from my small newt that this is important.

Good luck!

[rowan46]

first of all maks do need a fair bit of cool down time and the 127 is quite a large mak I would guess minimum 30 mins probably a little more. Atmospheric conditions do play a part there was a bit of mist at higher altitudes over me last night and I believe vega is not as high in the sky now as it was and the closer you get to the horizon the fuzzier the stars as there is more atmosphere to interfere Its most probably a combination of cooldown and atmosphere

[nightfisher]

combination of all three, maks taks a good while to cool down, my 140 takes ages, they also seem to give their best in really good seeing, but when its good seeing they are superb.When i got my omc140 i tried it out and really thought i had a turkey but lots of moisture in the atmosphere, a month later i got a really clear night and WOW

[barkis]

Do you keep the scope indoors when it isn't in use?

If so, the cooldown requires at least an hour, possibly more.

The several elements that make up the optical system, and contribute to the final image, will all cool at different rates, and they all need to reach ambient temperature before the optimum performance is possible.

It is almost a closed system, which can also resist rapid cooling.

Ron.

[Jimmy Stix]

Do you keep the scope indoors when it isn't in use?

If so, the cooldown requires at least an hour, possibly more.

Yes I am keeping it indoors. It's so new I am in and out of the original box and bubblewrap at the moment.

This is great feedback and help guys. Thanks so much for such a rapid response and the benefit of your experience.

I luuuurve this forum! What a comfort to know I have this vast pool of knowledge at the touch of a button.

[Astro_Baby]

I'd agree as well, most probably poor seeing conditions and cooldown time.

Under good seeing stars should be pinpoint at the centre od the field. They may go mushy at the outer edges because the supplied EPs are not that great.

With that said I found te 25mm to be acceptable but was aced entirely by a better quality Plossls from Celestron, Vixen and TAL.

[jgs001]

My skymax 102 needs about 40 minutes cool down and I keep it in the garage which is only about 5 degrees above ambient... from the house, 60 to 90 minutes I'd expect...

[themos]

Or you can keep it in a fridge...

[Dave S]

I had similar with my Skymax 102 on the first night. Turned out to be dew on the corrector plate.

Always leave it to cool down sufficiently with the lens cap on. I made the mistake of taking the cap of before i moved it outside.

Dave...

[Casus belli]

Yeah I was going to mention dew as a probable cause. Maks normally give very crisp images

[Jimmy Stix]

Thanks!

So I guess you would advise lens and eyepiece caps on and a cooling down time of 45mins to 1 hour.

If it is dew, is that anything to worry about and will it dry on it's own? I suppose it's the same as when you breathe on any glass right?

[valleyman]

Lot of dew where i live last night, within 30 minutes the telrad was soaking and useless. fitting a dew shield to it.....Might be a good idea to look into dew shields for your scope.

[Bizibilder]

Dew won't damage your scope but DON'T wipe it off!! Use a dew shield or dew heater - for the time being you could use a 12v (NOT mains!!) hairdryer with a battery. Even one of those "microwavable" bags that are used for soothing aches and pains can be used to wrap around the scope - for just long enough to evaporate the dew.

[Jimmy Stix]

Dew won't damage your scope but DON'T wipe it off!! Use a dew shield or dew heater - for the time being you could use a 12v (NOT mains!!) hairdryer with a battery. Even one of those "microwavable" bags that are used for soothing aches and pains can be used to wrap around the scope - for just long enough to evaporate the dew.

Can anyone tell me if Skywatcher make their own dewshields specifically for my Mak or can I get a universal fitting one?

[Watcher]

I've got the same 'scope and try to give it at least 1 1/2 hours on the cold. I take the lens cap off the objective lens and leave the 'scope pointing downwards slightly.

Word of warning - don't leave the controller outside for the cooldown period. They don't like the cold and it makes the display very slow to respond. i have seen it suggested that you put it in a sock to keep it warm. Batteries also can be badly affected by the cold so leave them indoors too until you need them.

[Jimmy Stix]

Sorry to dig this post "out from the depths" again but last night I had some problems once more.

As you may know I have had some success since I first posted this with stunning views of the moon and in particular a lovely look at Saturn yesterday morning.

Getting giddy about the clear skies last night I went out again and whilst it was a little breezier I hoped conditions were okay for my first good look at Jupiter. However by the time I got to my dark site it was around 20:40 already and Jupiter was by now down at around 12 degrees already. Once again I could not get it or the moons really sharp. I don't think dew was a problem and even though I had not let my Mak cool down for very long I had hoped for better than I got.

Was it that it was so low down? Do I need better eyepieces? I was using the 25mm I got with the scope. The 10mm was worse and the Barlow I got was a real fuzzy mess.

I got a reasonble look at The Orion Nebula despite the bright moon so I was disappointed that Jupiter was so poor.

Your advice would be much appreciated once again.

[Dave S]

I had the same issue last night. At the time you looked, jupiter would have been really low. Because of the clear skies there seemed to be a lot of atmospheric turbulence most likely from rising thermals and the fact that there was a lot of moisture in the air and maks DO need a lot of cooling. The slightest hint of residual warmth in the tube turns objects like jupiter into a boiling mass.

Dave...

[vulcan]

Jupiter was a bit fuzzy for me last night too. I've seen it much better. Near Full Moon is not the best time for viewing anything (including The Moon itself) as the bright atmosphere is fogging the view. Give it another couple of weeks. Also, the higher in the sky it is, the less atmospheric distortion. As it gets near the horizon, it gets progressivly worse.

[Jimmy Stix]

Thanks Dave and Vulcan.

An earlier start and a longer cool down are the order of the day then, although I realise there is not much you can do if the atmosphere is bad.

[John]

You may have reached the limits of the eyepieces that come with the scope. The 10mm and the barlow are not great, putting it politely. If you were to put an 8mm Tele Vue plossl or something of a similar quality into your scope you might be pleasantly surprised.

Having said that, when objects are low in the sky they get increasingly affected by the atmosphere and it's hard to get sharp images or good contrast and resolution.

[Jimmy Stix]

If you were to put an 8mm Tele Vue plossl or something of a similar quality into your scope you might be pleasantly surprised.

Thanks for your rapid response too John. I notice in my OVL catalogue that Skywatcher do their own plossl's. Do you rate these at all or would the Tele Vue be better? Would it not be best to match the manufacturers own design to my scope or is the quality of the eyepiece such that it is not a factor?

Sorry guys! Questions, questions, always with the questions!

[John]

Thanks for your rapid response too John. I notice in my OVL catalogue that Skywatcher do their own plossl's. Do you rate these at all or would the Tele Vue be better? Would it not be best to match the manufacturers own design to my scope or is the quality of the eyepiece such that it is not a factor?

Sorry guys! Questions, questions, always with the questions!

The Skywatcher plossls are OK but the Tele Vue ones are the best of that type available, in my opinion. You can use any brand of eyepiece in any brand of scope.

Have a browse around the eyepiece discussion and review threads - you will soon see a pattern emerging on the types that rate well as they get mentioned over and over again !.

[Staffy]

Where do you set up your scope? A nearby open window or door from a centrally heated house will cause lots of air disturbance and spoil your view. I also have the Symax 127. Half an hour seems to be fine for cool down time for my scope.