3x Barlow on Celestron Powerseeker 70az

[Tredelerch79]

Hi everyone,

It's been years since i last posted here after initially getting a Skywatcher Skyliner dobsonian which became impractical after i moved to a small flat. Now, with a young son, I've bought a Celestron Powerseeker 70AZ and last night i set it up.  

 

It came with 4mm and 20mm lenses and a 3x barlow. Last night i showed my son the moon and Jupiter, out of his mind excited (he is 3 and can name all planets in the solar system in order from the sun and tell you the hottest, coldest, smallest, largest he loves it all).  However I could only see anything using the 20mm lens with any images of the moon in the 4mm being a little blurry and Jupiter being totally blurred. I could just make out Saturn with the 20mm but really small and had to squint to recognise it, higher magnification with the 4mm was just nothing at all.  The barlow, forget it, everything is blurred all of the time. With my Dobsonian i got small but clear pictures of Jupiter, able to see the colours and even the red spot, i forget which lenses I had but i can check, perhaps a 10mm but ill confirm.

 

Today I have recalibrated the finderscope and its pretty much smack on. I did this by focussing on a window in an office block around 1 mile away. Both 20mm and 4mm lenses worked.  The barlow again does nothing, its like its smeared with vaseline.  

So is it me?  Is the barlow junk?  Maybe the 4mm is too strong and im missing the tiny bit of sky im looking for?  I don't think so because I can get something but just can't focus enough on it to get a clear picture. 

 

Any advice or help very welcome because id love to really keep my son interested and spark his curiosity further.

 

[Neil H]

Hi i had a x3 barlow with my first Telescope and was to much a x2 is better the eyepiece  that come with most telescopes are not good you need to look for plossl  eyepiece these are better optics  i am new to this so will leave some that knows more to tell you what to get 

I do use the celestron  zoom 8 to 24 and this works well on most Telescopes so may be worth a look at 

[pregulla]

I guess the problem is the switch from dob to 70mm refractor. Everything is going to look small or dim or both in comparison.

The barlow that came with the scope is probably of poor quality. Pair it with not the best eyepieces and high powers and you won't see much.

4mm is too much magnification for that scope as well.

32mm plossl and 7.1-21.5mm zoom should be a good starting set, and may be everything you need.

 

[Neil H]

34 minutes ago, pregulla said:

I guess the problem is the switch from dob to 70mm refractor. Everything is going to look small or dim or both in comparison.

The barlow that came with the scope is probably of poor quality. Pair it with not the best eyepieces and high powers and you won't see much.

4mm is too much magnification for that scope as well.

32mm plossl and 7.1-21.5mm zoom should be a good starting set, and may be everything you need.

 

 I was told that the 7 to 21 is not a good zoom to get the 8 to 24 is the better one my works well thats why they cost more no one gets the 7 to 21  i use my with a bst  x2 barlow never has a problem with image always sharp focus

[pregulla]

2 minutes ago, Neil H said:

 I was told that the 7 to 21 is not a good zoom to get the 8 to 24 is the better one my works well thats why they cost more no one gets the 7 to 21  i use my with a bst  x2 barlow never has a problem with image always sharp focus

Celestron 7-21 is indeed worse than 8-24mm, but there are other 7-21 zoom eyepieces that are fine. I was talking about Hyperflex 7.1-21.5, shorter focal length will allow some extra magnification without using a barlow.

[Alan64]

On 26/09/2020 at 12:14, Tredelerch79 said:

Hi everyone,

It's been years since i last posted here after initially getting a Skywatcher Skyliner dobsonian which became impractical after i moved to a small flat. Now, with a young son, I've bought a Celestron Powerseeker 70AZ and last night i set it up.  

 

It came with 4mm and 20mm lenses and a 3x barlow. Last night i showed my son the moon and Jupiter, out of his mind excited (he is 3 and can name all planets in the solar system in order from the sun and tell you the hottest, coldest, smallest, largest he loves it all).  However I could only see anything using the 20mm lens with any images of the moon in the 4mm being a little blurry and Jupiter being totally blurred. I could just make out Saturn with the 20mm but really small and had to squint to recognise it, higher magnification with the 4mm was just nothing at all.  The barlow, forget it, everything is blurred all of the time. With my Dobsonian i got small but clear pictures of Jupiter, able to see the colours and even the red spot, i forget which lenses I had but i can check, perhaps a 10mm but ill confirm.

 

Today I have recalibrated the finderscope and its pretty much smack on. I did this by focussing on a window in an office block around 1 mile away. Both 20mm and 4mm lenses worked.  The barlow again does nothing, its like its smeared with vaseline.  

So is it me?  Is the barlow junk?  Maybe the 4mm is too strong and im missing the tiny bit of sky im looking for?  I don't think so because I can get something but just can't focus enough on it to get a clear picture. 

 

Any advice or help very welcome because id love to really keep my son interested and spark his curiosity further.

 

Thank heavens you got the "Powerseeker" version.  I have the "Astromaster" 70mm, and with its proprietary, wonky focusser...

With these entry-level kits, you generally get a good, a very good telescope, specifically the main lens-assembly, the objective at the front of the telescope...

That's where it really counts.  Everything else that comes with a beginner's kit tends to fall short, comparatively.  But I have the same 4mm eyepiece, that I received with another, "PowerSeeker" kit, and it's actually quite the performer...

The 20mm is usable, but there is better, and for modest outlay.  I took my "PowerSeeker" 3x-barlow apart, to see what it makes it tick.  I found that it contains plastic lenses.  Simply chuck that barlow into a drawer, and as a curiosity, at most.

Your 70mm f/10 achromat(refractor) has a focal-length of 700mm.  A quality 2x-barlow, instead, is suggested for that telescope; that is, if it needs one at all.  That would make for an effective 1400mm focal-length.  To wit, the 4mm combined with a 2x-barlow will result in a power of 350x, which is actually too high of a power to use with your telescope.  Therefore, I would use the 4mm only, and for a power of 175x.  The telescope is capable of that, and a little more besides.

For satisfying close-up views of the planets, et al, one ideal is to combine a wider-angle 8mm or 9mm eyepiece with a 2x barlow, and for powers of 175x or 156x, respectively. 

Then, there's the Amici-diagonal that came with your kit.  You've got to have a diagonal, a necessary evil it is, and to keep the neck and back from aching and ailing.  I have one like yours, too...

It's not bad, but it's not intended for use at night; during the day, rather, for birds in trees, ships at sea, et al.  What you might want instead is a STAR-diagonal.  The term "star" says it all.  You can use your Amici-diagonal at night, for years if you'd like.  But if you did get a star-diagonal after all of that time, you might wonder why you didn't get it sooner...

 

Clear skies to you and yours!

Edited October 10, 2020 by Alan64

[Tredelerch79]

Thanks everyone for your advice.  I tried again tonight with slightly improved performance. Firstly i put the barlow in before the diagonal, that helped a bit. Worked better with the 20mm lens but still not at all with the 4mm, i suspect for the reasons given above.  

 

I tried both lenses without the barlow. Both worked a little better but still could not get that clear image of jupiter or Saturn. It was very bright and a little hazy, could that be to do with atmospheric conditions?  What i did try was to take the small bit off the lens cap instead of the whole thing, that seemed to make a difference too. Picture attached. But why would that help? 

Edited September 26, 2020 by Tredelerch79

[Alan64]

As I've understood, the planets have not been in a favourable position in sky for those dwelling along the upper latitudes of the northern hemisphere.  They're high enough for decent viewing here, as I live at the same latitude as that of Casablanca in Morocco, a bit below Spain.

The atmosphere is thickest at the horizon, and thinnest at the zenith(straight up).  The seeing gets progressively better as you go up higher from the horizon.  Trying to observe at or near the horizon is like trying to look through a glass jar of chicken broth, or a thicker soup even.

Placing a 3x-barlow in first will transform it into about a 4.5x, if I'm not mistaken.  Placing a 2x-barlow in first approximates a 3x...

I would think it allright for the 20mm, but definitely not the 4mm.

Then, you have me wondering about collimation.  Yes, refractors can use a bit of that, particularly those less-costly.  

Does your draw-tube, seen there with a somewhat matte-silver finish, rack in and out straight and true, firmly yet easily; or does it exhibit slop, looseness, wobbling?

That's an aperture-stop built into the dew-cap.  It looks to be either 30mm or 40mm in diameter, therefore an effective 30mm f/23 or a 40mm f/18 achromat is made manifest.  Such modes will exhibit no false-colour whilst observing the brighter objects.  It can be useful for the Moon, if too bright.  It may also be used to observe the Sun, during the day, but only with a safe solar-filter placed securely over the front of the refractor's objective; for example...

https://www.celestron.com/products/eclipsmart-solar-filter-for-70mm-refractor

However, I would not introduce that aspect to your child until they're much older.  It's an adult-age endeavour, rather.

Besides, a filter using Baader Planetarium solar-film is a better option... https://www.firstlightoptics.com/solar-filters/baader-astrosolar-safety-film-nd-50.html

You may make your own, and with the dew-cap you have now.  But it must be safe and secure.  You don't want a wind blowing the cap off whilst observing, nor to simply fall off.  You can shim the cap, and for a much tighter fitting.  Note the Celestron solar-filter is the same cap, but with screws to secure it in place.  The cap must be tested before each and every observance.

[Tredelerch79]

So i got my 10mm and 10mm wide lenses from my dobsonian. Got clearee view of Saturn, actually seen the rings, still small obviously but I could make it out.  Jupiter, still couldn't make out the colours and detail like with my dob, still just a bright sphere with a few moons. But clearly the 10mm lens is better and Im looking forward to seeing the moon with it. 

 

Now, how do I take photos with my phone?  I have a mount but the pictures are super bright and blurred.  Look at this one of Saturn. Miles better just looking properly. Is there a knack?

[Louis D]

You'll need to try decreasing the exposure on your phone.  Pull up the image tools and look for EXP or similar and drag the slider to -2 at least.  It's likely overexposing the image trying to make the black background 18% gray.

[Neil H]

Hi you can get a free app called open camera this gives you loads of options 

[Alan64]

21 hours ago, Tredelerch79 said:

So i got my 10mm and 10mm wide lenses from my dobsonian. Got clearee view of Saturn, actually seen the rings, still small obviously but I could make it out.  Jupiter, still couldn't make out the colours and detail like with my dob, still just a bright sphere with a few moons. But clearly the 10mm lens is better and Im looking forward to seeing the moon with it. 

Now, how do I take photos with my phone?  I have a mount but the pictures are super bright and blurred.  Look at this one of Saturn. Miles better just looking properly. Is there a knack?

It appears that even a 70mm aperture may make merry use of a variable-polariser, and to dim things down a bit. 

The objects within the FOV of an eyepiece are constantly on the move...

https://www.youtube.com/watch?v=8-9oFxYFODE

The camera must be held steady, and the shot taken in a fraction of a second, at least 1/10th.  I use a point-and-shoot camera.  That's my knack...

Jupiter is still too bright there, but that's through a 127/1016 reflector.

[RT65CB-SWL]

On 10/10/2020 at 19:04, Alan64 said:

It appears that even a 70mm aperture may make merry use of a variable-polariser, and to dim things down a bit. 

That’s what I do as well.

I find the my Baader Neodymium (a.ka. my ‘Swiss-Army knife’ filter), makes Jupiter appear pale blue.

Edited October 11, 2020 by Philip R

[Alan64]

Now, the aforementioned images were taken through a 4mm eyepiece, and at 250x.  I did not need to use a filter in those instances.  The camera will not collect much light well under a second.  

To the OP, you'll need at least a 2x-barlow to get closer, if not a 3x, but the higher you go in power the faster the object will move across the field-of-view.  Sub-second shots are mandatory if you're to catch them at or near their best, their sharpest. 

[Tredelerch79]

You're all brilliant thank you so much.