weak detail in jupiter 250px

[sam mayo]

i was viewing jupiter for the first time tonight and i could barley see 2 belts and it was bluryish is that down to colmination, i have been told by other that with the 250px dob they get great detail on jupiter,they have better eps but not sure what it is.thanks sam

[paul schofield]

I see reasonable detail of Jupiter with my 200p depending on sky conditions, using my 8mm BST or Radian 10mm+ barlow. It may be your collimation out a bit or maybe the eyepiece. Is it the supplied 10mm you are using ? was your scope at ambient temp ? How clear or transparent are your viewing conditions ? Others will be able to advise better as I am a relative beginner. Keep at it and I am sure your views will improve with time and experience. I still have not seen the G.R.S but pick out reasonable detail in cloud bands. In another month or so Jupiter will be better placed for viewing.

[umadog]

Eyepieces are important but not that important (within reason, of course). Collimation matters more with a fast scope, which is what yours is. My hunch is that if you have to ask whether your blurry views are "down to collimation?" then it's almost certainly the case that they are indeed down to collimation. Once you understand the procedure and are able to carry it out correctly then you'll know the scope is aligned correctly.

[iamjulian]

Could be the atmosphere was very turbulent. The clarity can vary night to night and hour to hour. Give it a couple more tries before you start fiddling.

[RikM]

As well as collimation and the steadiness of the atmosphere (the 'seeing'), you might need to wait for your main mirror to cool down to reach the same temperature as the air.

When it is considerably warmer than the air temperature, like if you just took it outside, then the mirror will contract slightly as it cools and give off currents of warm air which makes the air inside the tube unsteady, which will in turn make the image blurry. Not such a problem for large diffuse things like nebulae, but for detail on planets where you want the sharpest view possible it is better to let the scope cool first.

[cyborg421]

Yes all of the above,

Allow your mirror time to cool down and never forget the effect of the atmosphere on what you observe. I have a 250px and have seen Jupiter look like an orange blob and also on exceptional nights the detail has been amazing. Just be patient and you will be rewarded.

Simon

[Lenny147]

If you are using the supplied 10mm that would explain it to a point as its not the best quality ep, also the barlow supplied is not up to much. As others have said it could be seeing , i would spend a few nights observing first and go from there

[Carbon Brush]

All good suggestions from the above. But I'm another in the 'wait and see' camp. I have had difficulty making out more than 2 cloud bands, but have also seen the GRS. Both without touching the scope.

A good way to check for poor seeing, warm scope and poor collimation is to take a look at a bright star. Go to a high magnification and rack through focus.

If the star goes comet like, or oval, then there is a collimation issue.

If the star remains as a blob (albeit small) but the shape is unstable when small, then you have turbulent air. This could be in the tube or above you.

If the star goes to a small stable blob (not point) then this can be poor seeing, or it can be the scope optics.

If you can try a different high power eyepiece, repeat the test. Or rotate the eyepiece in the tube. I have seen some eyepieces with a little bit of astigmatism.

Do you have a hair dryer to hand when viewing? I have one in the obsy for removing dew, mostly at the end of the night. A quick waft of warm turbulent air across the front of the tube will makes stars vanish till you take the heat away. A very good example of how a bit of warm air can ruin the view.

Above all, be patient. I'm actually one of those who don't run out collimating a scope every time. When I bought my 200P, it been owned by a newcomer who knew little of collimation. Then it had an 80 mile ride in the back seat of my car, unboxed. Once home I checked collimation using tools in the light. There was nothing much worth adjusting. Since then routine checks have resulting in little adjustment. This scope has shown surface detail on Mars earlier this year. A good example of how scopes, once set, don't leap off collimation as soon as you turn your back. Probably if I banged the OTA on door frames and dropped it to the floor every time out, things would be different.

Wait and see. Hope this is useful.

David.

[faulksy]

i viewed jupiter the other night with 1 of my new e.p.s sky was steady but could just make out the cloud bands and 1 barge far from the best i have seen it, this was down to the sky conditions so wait and try again

[John]

I'd advise you to wait until Jupiter is higher in the sky before jumping to conclusions re: the scope. The viewing conditions for planetary observing have not been good of late (you are not far from me) and when I viewed Jupiter a few nights ago with my ED120 refractor I could see very little apart from the 2 main bands - that scope usually shows me loads of detail on the planet when it's well positioned and the seeing conditions are good.

When you are starting out it's so easy to blame disappointing results on the equipment when much of the time it's down to the viewing conditions being poor plus you are developing your seeing skills too.

[PorkyB]

My view of Jupiter can vary massively from one night to another, using the same equipment. One night it was a featureless blob, the next night I could clearly see the bands and that is with a small scope (90mmMak using a BST 8mm EP).

[sam mayo]

thanks for the replys i was observing for about 3-4hours but i do find it a bit overwhelming and am looking forward to my first star party(southwest oct) havent ever observed with any 1 else and i usually learn more from others in person. than myself,i struggled to focus on jupiter and it seemed very bright maybe to bright to see much detail,anyway the advice is great will carry on as is until the party and rope some poor sole into helping me lol.

i have tried the star test but cant see any lines seems a bit to blurry.none the less i am enjoying it besides a bad back witch doesnt help.

getting some new eps for the star party and would a barlow be recommended? if so i have budget of £50 each for 2 ep and whatever for a barlow.

hanks again for the reply s and patience,sam

[umadog]

That's fine. Don't worry about being overwhelmed. When you're new to this there's a lot to take in. Just keep in mind that your scope should be showing you a considerable level of detail on Jupiter at 200x or so. To re-cap the good advice you got: your ability to see detail on Jupiter will depend on collimation, seeing, Jupiter's altitude, your experience, the telescope's optics, and the eyepiece. It will take some time for you figure out how to get the best views and to see what your scope can deliver. Don't expect the results right away and do work at it. The star party will help a lot, even if it's just talking to people and getting advice. Here's what you can do now:

1. Learn to collimate your scope well and be prepared to tweak the collimation before each session.

2. Learn what bad and good seeing look like at the eyepice. Try to split the double double (epsilon Lyrea) near Vega. It's not a particularly hard split but on nights of poor seeing it won't be possible.

3. Learn what the meridian is in the sky and check when Jupiter reaches it. Use Stellarium. Note that Stellarium also lists an objects altitude above the horizon. Usually >30 degrees is needed for reasonable views but >50 degrees is better still.

4. You don't need to spend big bucks for a sharp eyepiece. The more expensive eyepieces are expensive because of the wide field of view. For planets you really only need a Plossl, and they're cheaper. It's true that with a wider field eyepiece you need to push the scope less often. But the view may not be as sharp near the edges of the wider field.

[Vega]

I collimate my 250 px roughly once every 3 months or so. As long as the collimation knobs are tight, it seems to keep it together well for this length of time. To collimate before every observing session would be an offput for a beginner I would of thought. Any other thoughts anyone?

Considering the time of year, I reckon Jupiter's altitude was the main factor for poor viewing.

Cheers

[RikM]

I check my 250PX every time I use it because I have to carry it through the house and out to the garden. Most times the primary needs a slight tweak but it's a 2 minute job so no big deal.

[knobby]

I collimate my 250 px roughly once every 3 months or so. As long as the collimation knobs are tight, it seems to keep it together well for this length of time. To collimate before every observing session would be an offput for a beginner I would of thought. Any other thoughts anyone?

Considering the time of year, I reckon Jupiter's altitude was the main factor for poor viewing.

Cheers

Don't over tighten though!

[sam mayo]

last night was better i managed to split a double easily enough and Jupiter was better but i now see what you mean buy viewing conditions,i could see the atmosphere, waves? interrupting the view and i think it might have been slightly cloudy due top it being dimmer at times than others,when i performed the star test i couldn't really make out the lines but the circle seemed to be uniformed all the way round.

i was waiting eagerly for jupiter to reach 30 degrees(or higer) but by the time it did (roughly 4am) it had clouded over:(.

i Saturn visible before it disappears i know it sets roughly the same time as the sun but would like a glance with the binos!.

thanks for the help sam

[LeeB]

As well as the above , you have to train your eyes, you are asking them to investigate minute subtle differences in shade on a micro scale, your legs wont run a marathon unless you practice , its the same with eyes. learn to relax them , a number of famous astronomers used to put cloths over their heads for half an hour prior to observing. I find I see better if I dont use a screen or watch tele for at least a hour prior and no reading either just relax in a dark enviroment. In fact just sitting next to the scope for the hour it takes to cool with your eyes shut works wonders.

Then you need a steady night , then you need a collimated scope, then you need decent eyepieces your scope is similar to mine and for planets I still like orthos. aim for a smaller sharper planet than a big blurry one.

Then spend time it will come in out of clarity most of the time and in those short bits of great seeing the details emerge.

[John]

Do remember to allow your scope time to cool off before trying to view things at high power. If the scope has been stored inside it will need 30 mins or so to cool before you will get a steady image. More cooling time will be needed when the nights get colder.

[sam mayo]

i have been letting it cool for about an hour before use,just orederd some solar film from flo looking forward to a bit of sun action :grin:

[Lenny147]

Be careful with the sun as I believe large dobs are not the best for solar viewing, in sure someone with more knowledge will tell you that

[sam mayo]

i was just going to use the cap that comes of the cover will reduce appature that should be ok then but please coorext if im wrong,which o probably am

[John]

i was just going to use the cap that comes of the cover will reduce appature that should be ok then but please coorext if im wrong,which o probably am

Only if you cover that small aperture completely with Baader Solar film, tape the cover firmly on the scope and keep the caps on your finder too. You can't take any risks when observing the Sun whatsoever.

[LeeB]

those damn finders burn your head if you forget.......,

[sam mayo]

thanks will do,was going to make 1 for the finder so i can find the sun heard it canbe a pain