New scope free dust!

[Desmond]

Hi,

I was lucky enough to get a new Skywatcher 72ED for Christmas and on opening it, I saw dust on the lens. Having tried to blow it off with a rocket blower, I have discovered it to be inside the tube.

The vendor says this will not effect performance, however I'm not that pleased to find dust in a new scope.

Any thoughts on how this might or might not effect my images would be welcome.

Should I kick up a fuss or this this fine and I can relax?

Some camera phone images attached for reference.

Thanks in advance!

 

[fifeskies]

That's a fair amount of dust to be honest.

I would not be happy with that , I am into astrophotography and it would be a bother and impact photography (but can be processed out).

 

For visual use only it will not have significant impact, but still undesirable in a new scope.

 

If this was new any decent retailer would exchange it if there is stock available, but supply might be an issue just now.

 

Can you tell if this is between the elements or is it on the back of the lens cell , if it is between then there is no real remedy without full disassembly

 

If it is inside the OTA at the back of the cell then you can try blowing it out with an air duster on a long silicon tube, but it is likely to recirculate and land back on the glass. Maybe a vacuum hose on low power and an air duster together could remove it from inside the OTA

[tooth_dr]

I recently received a brand new scope of different brand, and it was completely dust free. I don’t think it’s unreasonable to expect it to be dust free on the inside.

27 minutes ago, fifeskies said:

I would not be happy with that , I am into astrophotography and it would be a bother and impact photography (but can be processed out).

That dust wouldn’t show up on an image nor impact it in any perceptible way.  The dust needs to be much closer to the sensor to show up ie on the glass cover slip or the sensor itself. Dust on any additional filters will show up but will be large in comparison.  Dust on the lens cell like above won’t be seen. 

Edited December 31, 2020 by tooth_dr

[John]

It won't affect the performance but it should not be there on a new scope. All the new ones that I've bought were delivered with pristine optics. Pristine all over in fact.

Under normal circumstances I would ask the vendor for a replacement but things are far from normal currently

[fifeskies]

 

The dust needs to be much closer to the sensor to show up. 

this is true , however a lot of large dust particles can cause some scatter and will degrade the sharpness of some of the brightest stars, you wont see the actual dust itself on the image but the effect can be there for long exposures.

A small amount of small dust dots will be largely invisible and not impact things significantly, so can be largely ignored

Lens clips in the cell can cause bright stars to show "vanes" , large non round dust particles can create similar unevenness with bright stars on longer exposures , anything like an eyelash on the lens could be a problem depending on the system

 

Sometimes attempting to clean light dust can actually make things worse and as tooth_dr has pointed out most of the time dust will not have any significant impact

Edited December 31, 2020 by fifeskies

[Desmond]

3 hours ago, fifeskies said:

That's a fair amount of dust to be honest.

I would not be happy with that , I am into astrophotography and it would be a bother and impact photography (but can be processed out).

 

For visual use only it will not have significant impact, but still undesirable in a new scope.

 

If this was new any decent retailer would exchange it if there is stock available, but supply might be an issue just now.

 

Can you tell if this is between the elements or is it on the back of the lens cell , if it is between then there is no real remedy without full disassembly

 

If it is inside the OTA at the back of the cell then you can try blowing it out with an air duster on a long silicon tube, but it is likely to recirculate and land back on the glass. Maybe a vacuum hose on low power and an air duster together could remove it from inside the OTA

Thanks for the reply - much appreciated.

Agreed - it's a lot of dust and I am requesting a replacement. If no stock, then a refund and I'll shop elsewhere. My wife bought it for me and sadly did not get it from FLO as I had requested.

 

Edited December 31, 2020 by Desmond

[Desmond]

15 minutes ago, fifeskies said:

 

The dust needs to be much closer to the sensor to show up. 

I would disagree slightly , large dust particles can cause some scatter and will degrade the sharpness of some of the brightest stars, you wont see the actual dust itself on the image but the effect can be there but tiny dust will be largely invisible and not impact things significantly.

Lens clips in the cell can cause bright stars to show "vanes" , large non round dust particles can create similar unevenness with bright stars on longer exposures , anything like an eyelash on the lens could be a problem depending on the system

 

Sometimes attempting to clean light dust can actually make things worse and as tooth_dr has pointed out most of the time dust will not have any significant impact

I did grab a few quick frames of Andromeda (moonlight intrusion to the left) and noticed top right the strange artefact around one of the stars there. I have looked on way better images than mine and never seen that. I wonder if this is the dust? This was the first night out and this is when I saw the dust as I was checking the lens for dew.

[fifeskies]

To be fair (to your wife) I think FLO were not holding stock of this scope and what was arriving was already allocated.

Other retailers could certainly do with raising there game to FLO levels.

[Desmond]

55 minutes ago, fifeskies said:

That's a fair amount of dust to be honest.

I would not be happy with that , I am into astrophotography and it would be a bother and impact photography (but can be processed out).

 

For visual use only it will not have significant impact, but still undesirable in a new scope.

 

If this was new any decent retailer would exchange it if there is stock available, but supply might be an issue just now.

 

Can you tell if this is between the elements or is it on the back of the lens cell , if it is between then there is no real remedy without full disassembly

 

If it is inside the OTA at the back of the cell then you can try blowing it out with an air duster on a long silicon tube, but it is likely to recirculate and land back on the glass. Maybe a vacuum hose on low power and an air duster together could remove it from inside the OTA

inside - but I cannot tell if it is between elements or not!

[Desmond]

1 minute ago, fifeskies said:

To be fair (to your wife) I think FLO were not holding stock of this scope and what was arriving was already allocated.

Other retailers could certainly do with raising there game to FLO levels.

She did say they did not have it in stock. All is forgiven BTW

[fifeskies]

4 minutes ago, Desmond said:

I did grab a few quick frames of Andromeda (moonlight intrusion to the left) and noticed top right the strange artefact around one of the stars there. I have looked on way better images than mine and never seen that. I wonder if this is the dust? This was the first night out and this is when I saw the dust as I was checking the lens for dew.

 

Dust on the lens cell is way outside the focal plane and would be unlikely to create a localised effect on a small part of the image.

It would possibly cause some loss of clarity over the whole image due to diffraction effects but that artefact is most likely caused from something else as it is so localised

[FLO]

25 minutes ago, Desmond said:

My wife bought it for me and sadly did not get it from FLO as I had requested.

Bless her. We had probably sold out 🙂 

Steve 

[wimvb]

Dust in your light path is just like any other obstruction, it will decrease the light throughput (aka dust bunny if it's close enough to the sensor) and spread light by diffraction. Both effects will decrease contrast. If it's as bad as your pictures show, I would never be happy with this scope and contact the dealer for a replacement or a refund.

[Desmond]

This was the initial response:

Hi Peter,
They look like dust particles on the inside that won’t affect the performance.

Kind Regards,

No apologies or acknowledgements that this is not how a scope should be from new.

Asked for a replacement, if no stock, then I'll go for a refund.

I have not mentioned the vendor here as they have a chance to clear their name. If they chose not to then I will share the name to save others. 

 

 

[heliumstar]

If particles are between lenses return it. Otherwise clean it Q-tip and alcohol will do the job.

[Mr Spock]

I don't think any purchaser should be in the position of having to disassemble a scope to clean it. The supplier needs to either replace it or clean it. There's no excuse to send out a scope in this condition.

The amount of dust makes me wonder if it is new at all.

[wimvb]

2 hours ago, Desmond said:

This was the initial response:

Hi Peter,
They look like dust particles on the inside that won’t affect the performance.

Kind Regards,

No apologies or acknowledgements that this is not how a scope should be from new.

Asked for a replacement, if no stock, then I'll go for a refund.

I have not mentioned the vendor here as they have a chance to clear their name. If they chose not to then I will share the name to save others. 

 

 

So, how many dust particles does it take before performance is affected?

Imo, return the scope for a full refund, then buy one from a reputed dealer. 

[fifeskies]

12 minutes ago, wimvb said:

So, how many dust particles does it take before performance is affected?

I guess its a mote point ..............................  I'll get my coat.

 

Its unlikely a few odd dust specks make any real difference but if it's new they should not be there.

[Desmond]

An update on this one for anyone following. I just got this from the vendor:

These telescopes like any refractors or cassegrains aren’t sealed at the back of the scope so dust will get in I’m afraid. It’s quite common and even a brand new replacement may have similar particles.

Seems like a cop out to me. Any thoughts?

I have requested a replacement or refund again.

 

[theropod]

Long ago the quip, “The customer is always right”, died in a back alley knife attack. The perpetrator? Greed. Your NEW scope should come in NEW condition, and any dust inside the OTA should rightfully be placed there by the owner. Part of the thrill of a new scope is worrying about every little thing one does somehow harming the precious. That cherry has been picked from the top of your sundae. Replace or refund.

[Stu]

48 minutes ago, Desmond said:

An update on this one for anyone following. I just got this from the vendor:

These telescopes like any refractors or cassegrains aren’t sealed at the back of the scope so dust will get in I’m afraid. It’s quite common and even a brand new replacement may have similar particles.

Seems like a cop out to me. Any thoughts?

I have requested a replacement or refund again.

 

I would get it refunded if I were you. It should come from the factory with the caps in place, in a bag and boxed up, so no dust should get in before you open it up.

It will have no impact on what you see, but it will bug you and will potentially reduce the resale value. That’s not the point though, your wife paid for a pristine new scope, and that’s what you should get.

[jock1958]

1 hour ago, Desmond said:

An update on this one for anyone following. I just got this from the vendor:

These telescopes like any refractors or cassegrains aren’t sealed at the back of the scope so dust will get in I’m afraid. It’s quite common and even a brand new replacement may have similar particles.

Seems like a cop out to me. Any thoughts?

I have requested a replacement or refund again.

 

You've given the vendor a chance and he's replied with a load of old tosh to put it politely!!  as others have said it should have been received in immaculate condition inside & out, stick to your guns and go for the refund.

[KP82]

1 hour ago, Desmond said:

An update on this one for anyone following. I just got this from the vendor:

These telescopes like any refractors or cassegrains aren’t sealed at the back of the scope so dust will get in I’m afraid. It’s quite common and even a brand new replacement may have similar particles.

Seems like a cop out to me. Any thoughts?

I have requested a replacement or refund again.

 

While dusts on the lens are unavoidable, the amount that was seen on your brand NEW scope is not acceptable. My gut feeling is this scope was a open-box customer return.

Reading the reply from this vendor, I'd say get a refund and buy somewhere else.

Edited January 2, 2021 by KP82

[John]

I've heard that same lame excuse before from a vendor, whom I won't name here. I wonder if it is the same one ?

Get a refund or a replacement. The scope should be pristine as it's new.

 

[John]

3 minutes ago, John said:

I've heard that same lame excuse before from a vendor, whom I won't name here. I wonder if it is the same one ?

Get a refund or a replacement. The scope should be pristine as it's new.

 

This was the incident that I was referring to:

https://stargazerslounge.com/topic/361574-brand-new-esprit-100ed-dustparticle-issue/