SiriusB

RE: RA left x1 not working~ turn the motor off & the Earth will spin & the correct 1x  rate to move the object across the FOV. 😉

I can't offer any great insight into reducing backlash other than from my non pro eq5 it's a case of adjusting any slop in the gears to a 'best fit'

Then going over the whole procedure again.

Note: too tight a mesh of the gears is much worse than a little too loose as you may strain/damage something. Spur gears need a slight amount of play (cigarette paper between them maybe?)

Along with M42, M27 is another object that sometimes appears vaguely green to me in only 120mm.

Anyone with the ability to see red in DSO's needs to donate their eyes to medical science.😉

As an aside, double stars colours generally appear richer in an achromat (green star anyone?)~it's not  a 100% accurate rendition, but no less pleasing for all that.

23 hours ago, Don Pensack said:

To be fair, ANY contrast enhancement will still be.....contrast enhancement.

But some economical filters with better bandwidths include DGM, Orion (US), Omegon, SkyWatcher, Zhumell

 

Any chance you could expand on this please for the benefit of all?

I'd been given  to believe the best(bandwidth) nebula filters work best with larger scopes due to light loss? If you've only a small scope......

Thanks.

We're all different. Think hard what's acceptable & what's not to you.

Absolutely my 1st choice for moon has always been one of my volcano top orthos.

Generally i'm not very fussy about distortion in the outer field of view, however on lunar i really notice it in a bad way,hence the orthos win out.

Whether you'll get on with the narrow field of view is another matter. A Fujiyama should be a little better than my orthos performance wise.

If you want a wider field, i think suggestions have already been made, something around 60deg with good sharpness to the edge?

That said, last time i looked @ moon was with a £20 plossl & it really did look very good IMO.  Quite suprised.

Slightly off topic, but flocking seems to work well for the moon.

I don't want to panic you but if you can't clean it, keep it well away from your other optics!

   Seen a lot of fungus on camera optics, but until relatively recently not on astro optics.???

The fungus initially feeds on the lens coating, if it gets a strong foothold it will eventually etch the glass.

It will spread~ i've had camera lenses,stored in fairly dry conditions 'infected' from one bad one.😬

Making sure optics are dry before packing away is helpful in avoiding the issue. I don't think lens caps help in this respect if there's any damp present when you put them on. EP's never used to come with caps,which was slightly better fungus wise.

You could try different solvents until you find one that works. Nothing much will damage the glass, the coatings (presumably there is one on the reticle) may or may not be effected. There's hard & soft lens coatings~ i found lighter fluid very good for cleaning old camera lenses, it did however fetch the basic  magnesium flouride coating off a skywatcher O.G.nicely. Tread carefully!

Canada Balsaam was traditionally used to cement lenses together, relatively straightforward to soften. However I suspect it's not much used now, probably some sort of  optical epoxy??

If you do get it seperated cold cream is one thing recommended for removing the fungus, will be a slow job however.

Good luck.

On 06/01/2021 at 13:35, mikeDnight said:

In line with my philosophy, and of course my nature, SIMPLE works well for me!

Your're almost there Mike.

I don't have enough astro filters to worry about storage.

But going back to the days of 35mm film, loads of 49 & 55mm filters.

You could get male & female end caps for filters, i think they were called "stackers" or some such. nicely made of anodized aluminium by hoya & similar.

Safe,compact & airtight? storage, with ready access.

No idea if avaiable in astro sizes~ but maybe should be.

Now if i can remember where they are???, i'll post a pic~ don't hold your breath though.😁

SCT cools down quicker due to thinner corrector plate~ (apparently), never owned an SCT, must add to my'astro to do' list.

I can  say, even my small mak 127 takes a good while to cool down properly...

Also My Mak's never yet needed collimation since i bought it & initially adjusted up.

Apparently SCT's are often out of collimation,though there's plenty of info out there on how to tackle this, so no biggie.

I don't know, but if originality is a concern a simple non permanent solution would be to line it with flocking material.

You should be able to do  this without  even taking the silicone backing paper off.

Hello Johnathan,

                            I find SGL members always keen to help, but from your list you've set a seemingly impossible task!??

Some points for consideration:

1) I doubt you'll find 'better' views than your existing telescope in a more portable setup. It really is best bang for your buck in performance to price stakes.

2) If you want to do AP, (bearing in mind i don't @ present) realistically eq5 for an entry point? Bought one this year for visual use & quite frankly it's going to be as much a pain to carry outside as a 200p.

I can just move it about the garden with a evostar 120/150 installed, but needs breaking down to bring in/out.

So some serious 'man-up' juice required or a bit of a rethink? 😄😄

3) For visual use, a small to medium refractor on alt-az stand suits many people~quick set up etc.

4)goto,imaging & ease of transportation~tricky.

5)Keep your dob, buy a smaller Refractor or Mak as a complement. If you're dead set on imaging @ a future date maybe an 80ED would be best?

Sorry if that's not what you wanted to hear, Might be some better advice along later.😉

I'm sure there will be a visual back available without that dreaded😉 36.4mm thread.

Suggest you remove the existing back & carefully measure the thread dia such that someone can point the way.

I had to buy an adapter for my SW mak127 when i fitted a standard 2" visual back, i suspect it may be more straightforward with a C90.

To take 36.4mm dia  threaded  accessories.

This was a relatively common Japanese fitting once upon a time.

I still have a  beat up vixen 36.4mm eyepiece from the 80's

The good,the bad & the ugly.....

One rare night i had my mak 127 @ 375x on moon, no atmospheric wobble whatsoever in the view & not a soft image.

Could i see any more detail than @ half that mag? Nope.

Mag for what purpose Grumpy?

everyones' eyes are different but...

My rule of thumb is anything >  1.5x aperture in mm for planets, 1x aperture in mm for moon shows me no more detail. Your mileage may vary.

Doubles are a little different.

Often the seeing in UK doesn't allow me to hit 1.5x aperture for planets, regardless of aperture i find north of 150x  not happening on an average night.

That's just one persons location & optical train though.

Can you borrow a few EP's to try before you part with hard earned cash?

Plus one for the astro essentials plossls, bought a couple for my 'away' kit & i've been  pleasantly suprised.

Excellent VFM.

Does say on FLO website they're best for >F6 ~though i doubt you'll beat them for £30.

I'd hang on to it Pixies. It's a classic!

Originally  Aimed @ the SCT market  ie f10 i'd assume.

Johns' Vixen pic looks  exactly like a celestron badged one i used to own. I sold it when i got a 2" 32mm Konig, which personally  i prefered.

Bought quite a lot of ep's over the years & sold a few also,I mostly regret selling the ones i did.

Yes,but it's a few years ago now as UK is much better supplied with astro gear than it used to be.🙂 You should have no problems with Agena.

Import duty will be 20% vat plus the carriers fee around £8-10 'for sorting your import fees out', but i think if  the item is expensive there's another duty also?~ check HMRC website.

Thanks John,that's even better~ though it was the Tri Atlas fozzy bear mentioned that i was trying to recall.

In mighty fine condition if you've collected those 'used' Mr Spock.

I finally completed my circle t ortho collection this year with a used 25mm.

It's only taken me 35years! 😳

All circle t's ,but somewhat mismatched in comparison to your brood & my 18mm is showing it's mileage.(I think that was the EP i actually stuck to  on a particularly frosty night in the 80's)

The original 'set'  for many years comprised 4,6,9,12.5,18 & 25mm I believe.

The 5 & 7mm's were a relatively recent addition,so somewhat rarer.

Good luck with the hunt for a 5mm.

While you're hunting you probably need the 6mm also~ you know it makes sense.😉

Nortons goes out with me most nights, i've 3 old copys, 2 of which are suffering from dew fatigue. 🥴

My sky atlas 2000 went outside precisely once. A bit big to be practical. IMO

There used to be a laminated SA 2000, that would be the one to have if you insist on a paper atlas.

Also there was an online atlas available to download & print, went much deeper than any printed atlas, but the name & link now escape me.

Maybe someone else can chime in on that?

Enjoyed good views on 19th & 20th through my little 70mm. a gap in the skyline in just the right place from the back garden till about 6pm.

I knew viewing on  the 21st was an outside chance from the weather forcast & sadly it was  all too correct  for my location.

Such is UK astronomy.....a 200mile trip to Cornwall in '99 was similarly disappointing.

Did anyone in UK manage a glimpse on 21st? Please tell if you did.

But still,overall very pleased with the views on 19th & 20th.

& UK weather breeds a certain type of dedication in the nations'  Astronomers??

I've not seen Cassini division in 2020 using 70-150mm aperture. Saturn disappointing this year for me (apart from the Jupiter "fly-by")

My eyes not so young as they used to be either, 😉 but plus one for the low elevation being your primary problem.

Interestingly Jupiter has appeared far better  to me this  year (relative to it's low elevation), than i recall from distant memories past ??

"As an example, when viewing Mars again this weekend I ended up with a 'cloudy' circle all round it."

        That sounds like high haze, not very aesthetic but not necessarily bad for viewing planets. 

You can often get steadier seeing with some haze or even an Autumn mist,which sometimes give excellent seeing.

For faint fuzzies it's a bit of a kiljoy though.

On 16/09/2020 at 17:52, John said:

Interesting report.

I think the smallest aperture that I've seen the Cassini Division with is 70mm. That was the Tele Vue Ranger. I think that was at around 120x as well.

My old Tasco 60mm refractor showed the rings very clearly but I never managed to see the Cassini Division with that scope. Mind you I was using that at the outset of my observing so my experience was somewhat lower even if my eyesight was better !

Sounds right to me.

    I  can see the rings @ about 25x

,I've not been able to see the Cassini at all this Summer in 70-150mm, down to the low altitude, though others may have had more luck/skill.

When Saturn was high in the sky 15 or so years ago, Cassini division seen ok in 70 & 80mm scope at around John's suggested magnification.

For a bonus point there's seeing the Cassini division & then there's seeing it all the way round the rings, somewhat trickier & most likely needing more aperture.

Anyone for Encke's division?

Never seen it myself, back when i had a large enough scope to stand a chance Saturn was low in the sky like now.

......One for the future.

Thanks to all for your input.

Some very thought provoking replies, I feel i've learned something.

.....& to whomever corrected the title. 👍😉

22 hours ago, mikeDnight said:

I'd aim for an ED rather than an achromat and I wouldn't be too fussed about which one. I'm a firm believer that a good observer will get more out of a lower cost ED than a medeocre observer will get from a high end refractor. In reality, the performance gap between say a 4" fpl53 ED and a 4" fluorite apo has narrowed dramatically over the last 20 years, and definitely not worth losing sleep over. Just aim for the best you can afford, but bear in mind that a good quality diagonal and good quality eyepiece will make it sing. 

But, Mike, Would you choose a 3" ED over a 4" Achro ~for planetary, if you were on a tight budget?

Just curious, seeing as how you magic great sketches out of modest aperture i'm not going to argue.

I've taken most of my objectives out the cells, probably wouldn't reccommend unless theres a need, which it sounds like there is in this case.

If you're too cheap to but the tool a couple of small drill bits or allen keys will often work for removing the retaining ring, not that tight usually (round holes in all the synta fracs i've owned) But the tools are fairly cheap & can be used on EP's too, which always seem locked  tighter & more fraught with a potential slip of makeshift tools &..... hey ho, one scratched field lens later....you wished you'd bought the proper tool.

My main caution would be in the removal & particularly the replacement of the lens elements. sometimes they stick part way,sometimes they really stick too!

When replacing  element,s  you may want to invert the lens cell & gently push both elements up together with a soft cloth, other way round sometimes you get a nasty [removed word] of glass on glass when one element suddenly 'unsticks' itself.

.....Just so you can learn from anothers mistakes.😉