DayStar Filters 140mm-Aperture Energy Rejection Filter (170mm Cap Diameter)

DayStar Filters 140mm-Aperture Energy Rejection Filter (170mm Cap Diameter)

DayStar Filters 140mm-Aperture Energy Rejection Filter (170mm Cap Diameter)

B&H # DAE170N140 MFR # E-170N140
DayStar Filters 140mm-Aperture Energy Rejection Filter (170mm Cap Diameter)

Show MoreLess


Now Viewing:

Special Order
Expected availability: 7-14 business days

Product Highlights

  • For Use on Refractor and Maksutov OTAs
  • Reduces Heat Load on Filter Assembly
  • Absorbs or Reflects UV and/or IR Light
  • For H-alpha, Sodium, Helium D3 Filters
  • Inside Diameter of Cap: 17 cm (6.692")
Show moreShow less

SAFETY FIRST: Observing the Sun without the proper protection may result in serious personal injury, including permanent eye damage and blindness, and/or damage to equipment. Never point an optic at the sun without an approved solar filter on the front of the optic. For direct solar viewing, viewing the sun through an optic, or when using cameras with an optical viewfinder, ensure your filter is ISO 12312-2 (also written as ISO 12312-2:2015) certified. Never use photographic neutral density filters for direct solar viewing, viewing the sun through an optic, or when using cameras with an optical viewfinder.

B&H $500 Gift Card Dash

Share for a chance to win a $500 B&H Gift Card!

Share on Twitter

Share a favorite product for chances to win one of eight $500 B&H Gift Cards!
1 new winner announced every Monday starting Nov 5th!
Limit 1 entry per day: Come back every day to increase your chance of winning.

Be sure to mention #BHWishList when you share!

Congrats to our winners so far:

Next winner: Dec 17th

James Z. (Wk 1)

Ralph H. (Wk 2)

Arturo M. (Wk 3)

Rich P. (Wk 4)

Valeria A. (Wk 5)

Sabrina B. (Wk 6)

Official Rules


NO PURCHASE IS NECESSARY TO ENTER OR WIN. The B&H $500.00 Gift Card Dash (the "Sweepstakes") is void where prohibited by law and is sponsored by B&H Foto & Electronics Corp., 440 Ninth Avenue, New York, NY 10001 ("Sponsor"). It is not sponsored or endorsed by Facebook or Twitter in any way.

Entry Period/Methods of Entry. The Sweepstakes will run from on or about October 28, 2018 until on or about December 23, 2018 (the "Entry Period"). Entries received outside the Entry Period are void. Enter the Sweepstakes via either one of the following methods. (1) Share any product found on the B&H website (the "Website") on Facebook or Twitter via the dedicated links contained on the website using the hashtag #BHWishlist; or (2) Mail a postcard (postmarked during the Entry Period) containing your name, address, phone number, and email address, and indicate the subject(s), if any, about which you are interested in receiving future emails from B&H (e.g. photo, video, audio, computers, home theater, portable entertainment ) (optional) to: B&H $500.00 Gift Card Dash Sweepstakes, c/o B&H Foto & Electronics Corp., 440 Ninth Avenue, New York, NY 10001 (either option, an "Entry"). Entries must not, in the sole and absolute discretion of the Sponsor, contain obscene, provocative, defamatory, sexually explicit, or otherwise objectionable or inappropriate content. Entries deemed by Sponsor to be inappropriate will be disqualified. Entries owned by a third party, or the use of any trademarks, service marks, logos, brands, or products owned by a third party are not acceptable for entry into the Sweepstakes. Limit 1 entry per person, per day.

Winner Selection/Prizes/Odds. The B&H Social Team will randomly select a winner from among all eligible entries every Monday during the Entry Period, for a total eight (8) winners (each a "Winner"). Each Winner will receive a B&H Gift Card pre-valued in the amount of $500.00. No cash or other substitutions will be offered. Winner selection is in the sole and absolute discretion of the B&H Social Team. Any taxes are the sole responsibility of the winner. Winners will be notified and receive their prize at the email address associated with the account to which their Entry was posted or the email account provided with a mail-in entry. The odds of winning depend on the number of eligible entries received.

Identity of Winners/Eligible Participants. Winners will be identified by the email account associated with the Facebook or Twitter account from which their Entry was submitted or the email account provided with a mail-in entry. An email account holder shall mean the natural person assigned to such email account by the internet access or online service provider or other organization responsible for assigning email addresses for the domain associated with such email account. Any issues regarding the identity of a Winner shall be resolved by Sponsor in its sole discretion. The Sweepstakes is only open to residents of the United States that are at least eighteen (18) years of age on their entry date and is not open to employees of Sponsor, their immediate family, any person domiciled with such employees, or any affiliates or subsidiaries of Sponsor.

Entry Ownership/Entrant Agreements. Entrants retain full ownership and copyrights to their Submission. However, by entering the Sweepstakes entrants grant Sponsor permission to use their Entries for promotional purposes on their respective social media channels with proper credit. Entrants also agree: (a) to be bound by these Official B&H $500.00 Gift Card Dash Sweepstakes Rules; (b) that any claims related to this Sweepstakes shall be resolved individually without resort to any form of class action and that awards, shall be limited to actual out-of-pocket costs incurred in entering the Sweepstakes, and shall not include incidental or consequential damages or attorneys fees; and (c) that any actual or perceived ambiguities in these rules shall be interpreted by Sponsor in their sole discretion.

Limitation of Liability/Sponsor Modification/Cancellation Rights/ Choice of Law/ Venue/ Winners List. Sponsor is not responsible for incomplete entries or for failure to receive entries due to technical failures or human error of any kind. Winners agree that Sponsor will have no responsibility for losses or damage of any kind resulting from the acceptance, possession, or use of the prizes. Except where prohibited, participation in the Sweepstakes constitutes entrant's consent to the publication of his or her name by Sponsor in any media for commercial or promotional purposes without limitation or further compensation subject to Sponsor's respective Privacy Policies. Sponsor may modify or discontinue the Sweepstakes at any time and may disqualify from the Sweepstakes any person it determines, in its sole discretion, to have attempted to or actually tampered with or otherwise abused any aspect of the Sweepstakes. Entrants agree that in the unlikely event a dispute arises in connection with this Sweepstakes, it will be governed by the laws of the State of New York and heard exclusively in a court of applicable jurisdiction in the County and State of New York irrespective of any choice of law provisions to the contrary. To receive names of the winners by U.S. mail, please mail a self-addressed stamped envelope to: B&H Foto & Electronics Corp., Attn: B&H $500.00 Gift Card Dash Sweepstakes, 440 Ninth Avenue, New York, NY 10001. Any Winners List request must be received by B&H within one (1) year of the date the Sweepstakes is conducted.

Let us know how to reach you if you win!

Privacy 100% guaranteed; email address for contact purposes only


Already have a B&H account? Just log in tomorrow to enter again!

$0 VA Sales Tax Collected on This Item
Add to Wish List Item in Wish List

DayStar Filters E-170N140 overview

  • 1Description

Daystar Filters' 140mm-Aperture Energy Rejection Filter is designed for on-axis use with Refractor and Maksutov-style OTAs to reduce the heat load on your filter assembly by absorbing or reflecting UV and/or IR light while transmitting light in the desired spectrum. This ERF can be used with H-alpha, Sodium, and Helium D3 solar filters, but is incompatible with calcium wavelengths.

Choose the ERF aperture size to approximately match your refractor's objective aperture or Maksutov corrector plate. Select the correct filter cap size by measuring the outside diameter of the OTA's dew shield and choose the ERF with the smallest inside diameter that will fit over the dew shield. A set of screws is included to secure the ERF into place. This ERF's cap has an inside diameter of 17 cm (6.692").

UPC: 724696425533
In the Box
DayStar Filters 140mm-Aperture Energy Rejection Filter (170mm Cap Diameter)
  • 3 x Set Screws
  • Limited 5-Year Warranty
  • Table of Contents
    • 1Description

    DayStar Filters E-170N140 specs

    Packaging Info
    Package Weight 1.935 lb
    Box Dimensions (LxWxH) 8.1 x 8.1 x 3.1"

    DayStar Filters E-170N140 reviews

    140mm-Aperture Energy Rejection Filter (170mm Cap Diameter) is rated 4.0 out of 5 by 1.
    Rated 4 out of 5 by from I use the 140mm ERF aperture model with an Astro-Tech 130EDT The 140mm aperture (170mm cap diameter) will fit the dew shield of an Astro-Tech 130 EDT. I know what you're thinking: with a large aperture refractor (100mm+) and a Daystar Quark eyepiece, you can obtain an aperture advantage over a dedicated solar scope, which tend to exist in the 40-60mm range, and so perhaps you can possess a large aperture refractor, adapted for solar, and save some money at the same time. Well, sort of. The bad: This one took a while to arrive. In my case the time from order to arrival was a little over six weeks. Not unbearable, but you may need to plan your season of solar viewing in advance if the filter size that you need is special order. After a while I stopped asking B&H Photo for updates and just called Daystar directly. They did admit that my order was delayed - and in their defense it was over the holiday season - though for a while I wondered if it would ever show up, especially since my credit card had already been charged in full at the time of order. To be fair, Daystar were polite and transparent about what was going on. The metal cell on my unit (the thing that holds the glass) was delivered slightly out of round. By this I mean that the cell is perfectly round except along one side where it has obviously been dropped. I would blame the shippers but there is absolutely no indication of damage to the shipping box or packing materials. In other words I am fairly sure that the drop occurred at Daystar. It can be damaged easily this way since the filter is quite heavy - about 3 lbs. As it happens, the damage is not bad enough to cause a fitting problem, but it only just fits over my dew shield. The filter attaches to the front end of the dew shield. This has the effect of making the heaviest part of your scope even heavier. This is quite a problem when it comes to balancing. You will likely need a substantial mount to carry the filter and your telescope. For example, you'd probably be at the limit of utility on an Orion Atlas, especially for imaging. In my case I use the ERF filter with the dew shield completely retracted to assist in balancing, riding on an Astro-Physics 1100 GTO. So this ERF filter is not cheap to accommodate. To attach the filter to your dew shield, you are supplied with three nylon screws and some pieces of felt. I can't help but feel the nylon screws are laughably inadequate for holding something so heavy to the front of the telescope. Rather than test this assertion, I taped up the filter to the dew shield in addition to using the nylon screws. See photos. Keep in mind that the smaller diameter ERF units are going to be less heavy. The weight of the filter is problematic in another regard - it's heavy enough to tug on the dew shield and move it, even if the dew shield is secured with its own grub screws. Again, more tape can mitigate this. Avoid pointing the telescope towards the ground. The good: The filter arrives with a nice note from the owner at Daystar. While there are no 'instructions' there is at least a sense that you've bought something made to order and of professional grade. You are reliably informed that the filter does not in fact filter infrared rays, but only ultra-violet. I can't decide if this is a good or bad thing. For the money, I would like both types of radiation to be filtered before entering the telescope. To this end, I use a 2" UV/IR cut-off filter inside the telescope, in addition to the ERF, though this is probably redundant. Doing this doesn't seem to affect the image of the sun (I say this since I have tested the Quark eyepiece without the ERF, and only the 2" filter, through a 4" refractor. It looks the same). So the filter does appear to work. I have detected no heat issues or other problems since using it in combination with my Daystar Quark eyepiece. I expect that I could go without the ERF altogether and rely entirely on the internal 2" cut-off filter, but I'd rather be safe than melted. For this review I had considered testing my system without the 2" filter, but I just don't want to risk doing that. I feel that Daystar could provide some more specific information about when an ERF is required, and when it is not, besides the general guidelines that I can find on forums. The other effect of the filter is that it is a visual indicator that you have a filter on the front of your telescope while otherwise appearing to ignore all the warnings about pointing optics directly at the sun. This is comforting for those about to look through it. It's difficult to recommend this expensive ERF filter, but it's difficult to recommend not having one if your refractor is 5" or greater and you want to be absolutely on the safe side while observing the sun. It does allow you to concentrate on imaging or viewing the sun without worry, with a large aperture (for solar) and work on the various other imaging issues, such as focusing, lucky imaging, or achieving a full solar disk, if desired. So in this regard I am happy with mine and will be keep it.
    Date published: 2018-06-12
    • y_2018, m_12, d_4, h_17
    • bvseo_bulk, prod_bvrr, vn_bulk_2.0.9
    • cp_1, bvpage1
    • co_hasreviews, tv_0, tr_1
    • loc_en_US, sid_1265593, prod, sort_[SortEntry(order=RELEVANCE, direction=DESCENDING)]
    • clientName_bhphotovideo
    Be the first to review this item
    Customer Photos

    DayStar Filters E-170N140 Q&A

    DayStar Filters E-170N140 accessories

    See any errors on this page? Let us know.