New owner (Explorer 150p) - got a few questions

[LunarPoetry]

Hey there, cool forum you've got here! I've been reading it a fair bit recently. Not long ago I walked into a Currys, saw the display of telescopes and thought how cool it would be to get one. I've had a lifelong interest in space and astronomy, but never owned a telescope before. When I was much younger, I saw Saturn through a telescope (couldn't tell you what) and it blew me away. 

Anyway, following some research I realised that going into Currys and getting a telescope for a hundred-odd quid would not be the best way to get started. So began several weeks of seemingly neverending research and consideration. A lot to take in for sure. A few days ago I bit the bullet on something that had appealed to me from the start, but was about the limit of the budget.

So, I'm now the owner of a Skywatcher Explorer 150p on an EQ3-2 mount. I've only had the scope a few days and have used it twice so far. I have found the EQ mount relatively straightforward to operate once I had everything set up, which reassured me, as I had a few moments where I thought I would be in over my head with the mount. I got some breathtaking views of the Moon despite the glare, but the best part was Jupiter, very bright with visible moons and some colour banding visible in the atmosphere, which was better the more I concentrated. I looked at Mars briefly, and could just about make out hints of darker areas against the surface if I focused. I have to say that seeing these things with your own eyes, especially for the first time, is another level of awesome. 

So with all that out of the way, I'd like to pick your brains on a few points:

 

Eyepieces - I understand that the included 10 and 25mm eyepieces are decent but not amazing. I'm thinking of upgrading to the equivalent Skywatcher Plossl eyepieces. Is that a good enough step up, or should I be looking at anything else? I've read that BST Starguiders are great, but I'm a bit lost in terms of what MM I should be going for. If it helps, planets are slightly more what I want to look at from where I am at home (Bortle 7, it turns out - but I've used the scope on noticeably clearer nights here, and I'm not too far from a Bortle 5 area).

Taking care of the scope - Last night I'd been using the scope for an hour or two and frost had begun to form on the outside of the tube - when I brought it back in, the primary mirror fogged up a bit as I forgot to put the cap back on first. Today the mirror looks fine, but would that have done any harm? There seems to be differing opinions on the procedure for bringing it inside after using it outside in the cold. 

Dirt on the mirror -  I have what looks like a small piece of grass or something on the primary mirror, not sure how it got in there, but should I be worried about this? Image - I have not attempted to try and remove it myself and it doesn't seem to be causing a problem at the moment.

Diffraction spikes on planets - I must not have noticed this at first as I was too busy being stunned by what I was seeing, but somehow I became aware of it like it hadn't been there before. I looked this up and it seems attributable to the cross-shaped part that holds the secondary mirror, but they are fairly apparent now that I notice them more. I haven't attempted to collimate this scope yet, for what its worth. I assume its aligned well enough already as there are otherwise no blatantly obvious flaws with the image that I'm aware of, but I am going to collimate it when I get the right tool and am sure I won't mess it up. If this effect is inherent to the design then I can live with that, but is there any way to reduce or get around it? Was the atmosphere making it worse maybe?

 

Thanks and I appreciate your help!

[Spile]

Don’t worry about condensation or minimal marks on your mirror, they are not going to affect your views. I would bet that it’s not going to be an issue with collimation either. You definitely need to allow 30-40 minutes for your telescope to cool down outside before you attempt to use it. Views will be affected by conditions and dew can be right pain. But you did the right thing so just enjoy developing your skills. 

[Louis D]

Eyepieces: Lots has been written on this.  If you don't have astigmatism in your observing eye, you can get away with eyepieces that have less eye relief.  However, below about 10mm to 12mm of eye relief, and most folks complain about it being too tight.  For Plossls, this happens below 12mm or so.  I would go with BSTs at 12mm and below and with Plossls above that.  A good set would be 32mm and 20mm Plossls and 12mm, 8mm, and 5mm BSTs.  You also wouldn't duplicate your 25mm or 10mm eyepieces focal lengths, either.

You can try sealing the ends of the scope and the focuser with covers/plugs while outside to slow the inrush of indoor humidity that leads to condensation on optical surfaces before they have a chances to warm up.  Don't do this if it is more humid outdoors as in the summer when bringing it into an air conditioned house.  You'll trap the excess moist air inside the scope which is a very bad idea.

Dirt and debris on mirrors usually has little to no effect on optical quality.  Conversely, adding microscratches to a first surface mirror due to aggressive cleaning can lead to increased scattered light and lower contrast.

Diffraction spikes are perfectly normal.  To decrease them with curved spider vanes leads to spreading the light of those spikes across the field of view as a brightening of the background, decreasing contrast.  This can make seeing nebula more difficult.

[M40]

Hello and welcome to the site 👌. It's like a rite of passage getting grass on the mirror, it probably came from the cap, mine did   If you haven't already got one, buy a dew shield, that should be the first thing on your shopping list, second get a moon filter, they are not expensive and well worth the money. Very simple install, they just screw/unscrew on the eyepiece.

If you are bringing your telescope indoors at end of play, I would leave the cap off and leave the tube horizontal. As for eyepieces, you will have noticed already how fast stuff moves so I would look at a zoom, as speed of changing magnification is much improved rather than changing eyepieces. I start on the weakest setting to get the field of view you want then zoom in. 

All the best.

Edited December 10, 2022 by M40
spellin

[Alan64]

I have a 150mm f/5 Newtonian...

It's bright, in its own right, and versatile.

You can reduce and even eliminate diffraction effects with a variable-polariser...

[wookie1965]

A warm welcome to SGL, that is the exact set up I had 13 yrs ago for my first scope. I had loads of great nights with that seeing some wonderful objects.

Edited December 11, 2022 by wookie1965

[Moonlit Knight]

Excellent starting outfit, good choice. If I was to up grade eye pieces and depending how much money I had I would buy either some Starguider/BST explorers in the first instance and if I could not afford those I would buy Celestron Omni

[Neil H]

Hi I started with celestron omni they are a good start as I upgraded my scopes I up graded my omni eyepieces to BST, the omni eyepieces are just sat in a draw now 

[Louis D]

@Moonlit Knight and @Neil H, are Celestron Omni Plossls really that much better than FLO's Astro Essentials Plossls to justify them costing double the price (or more in the case of the 32mm and 40mm)?  The 6mm to 15mm COPs are only £16 less than the BST Starguiders at FLO while the 32mm and 40mm COPs are £10 more than the BSTs.  The COPs don't seem like much of a value proposition to me when starting out.  Am I missing something when people recommend them?

[Neil H]

The only reason I got them was a tight budget after buying scope and mount and were better than stock  when it you get them from China they are not dear , I got on well with them and I upgraded to BST now 

No they ant the best but still better than stock when starting out 

Edited December 11, 2022 by Neil H

[Moonlit Knight]

4 hours ago, Louis D said:

@Moonlit Knight and @Neil H, are Celestron Omni Plossls really that much better than FLO's Astro Essentials Plossls to justify them costing double the price (or more in the case of the 32mm and 40mm)?  The 6mm to 15mm COPs are only £16 less than the BST Starguiders at FLO while the 32mm and 40mm COPs are £10 more than the BSTs.  The COPs don't seem like much of a value proposition to me when starting out.  Am I missing something when people recommend them?

I just think the build quality is a little nicer. As I mentioned earlier I would of course recommend the BST in the first instance 

[Alan64]

The AE 32mm Plossl appears identical to my GSO 32mm...

The discontinued "Revelation" Plossls were most likely made by GSO as well.

The AE 32mm Plossl(23x), or a 2" 32mm 70° eyepiece, would assist the finder in finding objects to observe, and allow for panoramic views of the night sky.

[Franklin]

You'll hear lots of advise about letting your scope cool down before use and that is great advise. But also the opposite is true as well, especially when its cold outside and that is, when you've finished observing try to let your scope warm back up gradually. Don't bring a freezing scope straight back into a centrally heated living room, the optics will just mist over. Store it somewhere dry but not heated. A garage or porch for instance and place it on its side so any moisture will fall away. Regards the EQ mount, they look complicated but in reality they're just an alt-az set at an angle so you can track the stars. BST Starguiders are good eyepieces for the money and you can pick them up used for around £35 each. You don't need them all, I used to use the 25mm, 12mm, 8mm and 5mm and they served me well.

Edited December 11, 2022 by Franklin

[Mandy D]

16 hours ago, Franklin said:

You'll hear lots of advise about letting your scope cool down before use and that is great advise. But also the opposite is true as well, especially when its cold outside and that is, when you've finished observing try to let your scope warm back up gradually. Don't bring a freezing scope straight back into a centrally heated living room, the optics will just mist over. Store it somewhere dry but not heated. A garage or porch for instance and place it on its side so any moisture will fall away. Regards the EQ mount, they look complicated but in reality they're just an alt-az set at an angle so you can track the stars. BST Starguiders are good eyepieces for the money and you can pick them up used for around £35 each. You don't need them all, I used to use the 25mm, 12mm, 8mm and 5mm and they served me well.

Very pertinent advice, there. I never think about this, but I recall bringing my camera and lenses in from the Land Rover in Switzerland one time when it was -24 °C outside and my lenses fogged up on the inside as well as outside and took an hour or more in a warm place to clear! Thankfully, we do not heat the hallway where my telescopes are generally stored, so I may be OK. I don't have room to store my OTAs tilted, but might do it overnight after bringing them in, just in case.